text:
# Poisson Counts

6 posts / 0 new
Offline
Joined: 01/14/2010 - 16:47
Poisson Counts

I've asked about this before but I don't think I ever received any replies. Can OpenMx handle Poisson counts as observed variables? I have counts that are too small to treat as continuous Normally distributed outcomes and I need a way to model them. Any insights would be greatly appreciated.

salarim1 (not verified)
poisson gmm

hi
I want to add poisson likelihood function in growth mixture model for dependent variable.I need to model count variable.
Any insights would be greatly appreciated.

Offline
Joined: 04/19/2011 - 21:00
Yes, but it's not built-in

Yes, OpenMx can utilize the Poisson likelihood function, but it is not built-in. You will have to set up your model using an algebra objective or an R objective. See my examples below. Note that if your count variable takes relatively few unique values in your sample, you could consider ordinalizing it and doing the analysis as an ordinal thresholds model instead.

Let's first simulate some data for some simple examples:

dat <- cbind( rpois(1000,1), 1, rnorm(1000) )
dimnames(dat) <- list(NULL,c("y","x0","x1"))

If we want to do a simple Poisson regression, setting up the model to use a row-algebra objective would look something like this:

PoisAlgModel <- mxModel(
"PoissonAlgebra",
mxData(observed=dat,type="raw"),
mxMatrix(type="Full",nrow=2,ncol=1,free=T,values=c(1,0),labels=c("b0","b1"),name="b"),
mxMatrix(type="Full",nrow=1,ncol=2,free=F,labels=c("data.x0","data.x1"),name="xt"),
mxAlgebra( exp(xt%*%b), name="yhat", dimnames=list(NULL,"y")),
mxAlgebra( -2*filteredDataRow*log(yhat) + 2*yhat, name="rowAlgebra" ),
mxAlgebra( sum(rowResults), name="reduceAlgebra" ),
mxRowObjective(rowAlgebra="rowAlgebra",reduceAlgebra="reduceAlgebra",dimnames=c("y"))
)
PoisAlgFit <- mxRun(PoisAlgModel)

If we want to do the same analysis, but with an R objective, the code would look something like this:

Poisobj <- function(model,state){
modeldata <- model$data@observed b0 <- model$b@values[1,1]
b1 <- model$b@values[2,1] return(-2*sum(apply(modeldata,1,function(row){dpois(x=row[1],lambda=exp(b0*row[2] + b1*row[3]),log=T)}))) } PoisRModel <- mxModel( "PoissonAlgebra", mxData(observed=dat,type="raw"), mxMatrix(type="Full",nrow=2,ncol=1,free=T,values=c(1,0),labels=c("b0","b1"),name="b"), mxRObjective(Poisobj) ) PoisRFit <- mxRun(PoisRModel) Note that the two models' likelihood functions are not equal, but merely proportional. So, the parameter estimates should be the same (or very very close), but the value of the -2loglikelihood won't be. It sounds as though you have a longitudinal mixture analysis in mind, so naturally, your objective function will be way more complicated than the ones I demonstrated here, but I hope I've given enough to get you started. I might be able to help you more if you say more about the analysis you want to do. Finally, I feel I certainly should warn you about the problem of overdispersion, in case you don't know. If your count variable's variance appreciably exceeds its mean, even after conditioning on covariates, you should not trust the standard errors, confidence intervals, and likelihood-ratio tests from models using the classic Poisson likelihood. You would need to adjust those inferential results appropriately, or use a different objective function. The point estimates of your regression coefficients won't be biased by the overdispersion, though. Offline Joined: 11/08/2014 - 20:00 How about zero-inflated Poisson? I have poisson count data that is zero-inflated. I was wondering if OpenMx can handle that as well? Thanks! Offline Joined: 04/19/2011 - 21:00 Sure. No reason why not. The zero-inflated Poisson distribution simply has a slightly different PMF. Zero-inflated Poisson is a mixture distribution, but since it's a discrete mixture, it's pretty easy to work with. Let's first simulate some data for some simple examples: u <- runif(1000,0,1) v <- rpois(1000,1) y <- ifelse(u<=0.4,0,v) dat <- cbind( y, 1, rnorm(1000) ) dimnames(dat) <- list(NULL,c("y","x0","x1")) In the upcoming OpenMx 2.0, it will be practical to do this analysis with a row algebra fitfunction. I'll assume you're still using 1.3.2/1.4, so setting up the model with an R objective would look like this: ZIPoisobj <- function(model,state){ modeldata <- model$data@observed
b0 <- model$b@values[1,1] b1 <- model$b@values[2,1]
gam0 <- model$gamma@values[1,1] gam1 <- model$gamma@values[2,1]
lambda <- exp(b0*modeldata[,2] + b1*modeldata[,3])
w <- exp(gam0*modeldata[,2] + gam1*modeldata[,3]) / (1+exp(gam0*modeldata[,2] + gam1*modeldata[,3]))
iszero <- modeldata[,1]==0
return(-2*sum(log(iszero*w + (1-w)*dpois(modeldata[,1],lambda))))
}
ZIPoisModel <- mxModel(
"ZIPois",
mxData(observed=dat,type="raw"),
mxMatrix(type="Full",nrow=2,ncol=1,free=T,values=c(1,0),labels=c("b0","b1"),name="b"),
mxMatrix(type="Full",nrow=2,ncol=1,free=T,values=c(1,0),labels=c("gam0","gam1"),name="gamma"),
mxRObjective(ZIPoisobj)
)
ZIPoisRun <- mxRun(ZIPoisModel)

Note that the distribution has two parameters: the parameter of the Poisson mixture component (lambda) and the zero-inflation proportion (w). Both can be conditioned upon covariates, as I've done here, using a logit link for the zero-inflation proportion. In general, you can use different sets of covariates for the two parameters.

Edit: I might be able to be more helpful if you mentioned a few more details about your dataset and the analysis you're trying to do.

Offline
Joined: 01/24/2014 - 12:15
Some things germane to the thread topic

Currently, we plan to implement built-in support for count distributions in a future version of OpenMx, made available via the UI for IFA models.

There is a demo in the OpenMx test suite that shows how to do a generalized estimating equations (GEE) analysis of repeated measures on an overdispersed count variable. It includes a loop to calculate robust standard errors from the "sandwich estimator" of the regression coefficients' repeated-sampling covariance matrix. However, the specification in OpenMx is rather cumbersome, and it will usually be easier to do GEE in software designed specifically for it (e.g., the R package 'gee').

Also, I have a recent paper on the use of multivariate discrete distributions to estimate biometric variance components from overdispersed count data collected in a twin study.

format: plain


text:
# Trajectory package¶

## mesohops.dynamics.hops_trajectory class¶

class HopsTrajectory(system_param, eom_param={}, noise_param={}, hierarchy_param={}, integration_param={'INCHWORM': False, 'INCHWORM_MIN': 5, 'INTEGRATOR': 'RUNGE_KUTTA'})

Bases: object

HopsTrajectory is the class that a user should interface with to run a single trajectory calculation.

inchworm_integrate(self, state_update, aux_update, tau)

This function performs inchworm integration.

Parameters
1. state_update
1. list_state_newlist

list of new states

2. state_stablelist

list of stable states in the current basis

list of new states that were not in previous state list

2. aux_update
1. aux_newlist

list of new auxiliaries

2. stable_auxlist

list of stable auxiliaries in the current basis

list of new auxiliaries that were not in the previous aux list

3. taufloat

the time step

Returns
1. state_update
1. list_state_newlist

list of new states

2. state_stablelist

list of stable states in the current basis

list of new states that were not in previous state list

2. aux_update
1. aux_newlist

list of new auxiliaries

2. stable_auxlist

list of stable auxiliaries in the current basis

list of new auxiliaries that were not in the previous aux list

3. phinp.array

the full state of the hierarchy normalized if appropriate

initialize(self, psi_0, store_aux=False)

This function initializes the trajectory module by ensuring that each sub-component is prepared to begin propagating a trajectory.

Parameters
1. psi_0np.array

Wave function at initial time

Returns
None
make_adaptive(self, delta_h=0.0001, delta_s=0.0001)

This is a convenience function for transforming a not-yet-initialized HOPS trajectory from a standard hops to an adaptive HOPS approach.

Parameters
1. delta_hfloat < 1

The value of the adaptive grid for the hierarchy of auxiliary nodes

2. delta_sfloat < 1

The value of the adaptive grid in the system basis

Returns
None
normalize(self, phi)

This is the function that re-normalizes the wave function at each step to correct for loss of norm due to finite numerical accuracy

Parameters
1. phinp.array

the current full state of the hierarchy

Returns
1. phinp.array

the full state of the hierarchy normalized if appropriate

propagate(self, t_advance, tau)

This is the function that perform integration along fixed time-points. The kind of integration that is performed is controlled by ‘step’ which was setup in the initialization.

Parameters

How far out in time the calculation will run

2. taufloat

the time step

Returns
None

## mesoshops.dynamics.hops_storage class¶

class AdaptiveTrajectoryStorage

This is an object that manages storing information for a HOPS trajectory.

class TrajectoryStorage

Bases: object

This is an object that manages storing information for a HOPS trajectory.


text:
Sign up for our free STEM online summer camps starting June 1st!View Summer Courses

### At a carnival, $\$ 2,914.25$in receipts were tak… 08:40 Other Schools Need more help? Fill out this quick form to get professional live tutoring. Get live tutoring Problem 57 Three coworkers work for the same employer. Their jobs are warehouse manager, office manager, and truck driver. The sum of the annual salaries of the warehouse manager and office manager is$\$82,000$ . The office manager makes $\$ 4,000$more than the truck driver annually. The annual salaries of the warehouse manager and the truck driver total$\$78,000$ . What is the annual salary of each of the co-workers?

my share of groceries was $\$ 19.95,$my other roommate's share was$\$22.05$ and Sarah's share was $\$ 40\$

## Discussion

You must be signed in to discuss.

## Video Transcript

so let me know. What? Where? How much is that? You the office manager. We are traveling with D. So from the information from the question we have deputy U S O. We could you know 92,000 on the office manager. Ah, my honesty equals far 1000. And we're how Plus that Jack Trevor, In coach, you're 78,000. Do not want to country. So from going to every anthem and we subject them which we're gonna dump you unless the could you 72,000 and excellence them is the and in the culture question three, it means them we have money. Definite solution here. So infinite. So shin one particular solution would be And we fixed that that that that that the take Trevor will be equal Julissa 20,000 and then on the office. Ah, uh, the office manager must be Go do gently phone 1000 we're how we could do. Um front de I wasn't But even though it's infinite, sirs and we need to respect you, Uh, on Domenico Alberti on w says that they must be credit in the song of the smaller than 80 a smaller than, uh, a 78. 78,000 on down. So the, uh, the office manager must be great credit than the tea here is well.


text:
# IEEE Graphs Horizontal Alignment

I am using IEEE TVCG LaTeX Template and would like to insert multiple images next to each other using the following code:

\begin{figure}[h]
\centering

\begin{minipage}{0.45\textwidth}
\centering
\includegraphics[width=0.9\textwidth]{universe} % first figure itself
\caption{Universe}
\end{minipage}\hfill
\begin{minipage}{0.45\textwidth}
\centering
\includegraphics[width=0.9\textwidth]{figure} % second figure itself
\caption{Bar Plot}
\end{minipage}

\end{figure}

However, due to the template, the page is divided into two parts and hence the images are not aligned next to each other in a horizontal manner. How can I use the the following code to align the codes next to each other?

Thanks!

Tried 'figure*' environment:

\begin{figure*}[h]
\centering
\begin{minipage}{0.45\textwidth}
\centering
\includegraphics[width=0.9\textwidth]{LeNet_300_Accuracy} % first figure itself
\caption{LeNet 300-100-10 Training \& Testing Accuracy}
\end{minipage}\hfill
\begin{minipage}{0.45\textwidth}
\centering
\includegraphics[width=0.9\textwidth]{LeNet_300_Loss} % second figure itself
\caption{LeNet 300-100-10 Training \& Testing Loss}
\end{minipage}

\end{figure*}

But this is not helping as well.

• Please extend your code fragment to complete all document, which reproduce your problem, As already mentioned, for figures which span two columns, you should use environment figure* which move figure on the top of the next page from point of its inserting. – Zarko Mar 20 at 19:54
• I tried with 'figure*' environment, but it's not helping. Added code to question – Arun Mar 22 at 9:33
• Your code fragment works well in my test document, however, we don't know yours. Please, extent your code fragment to complete small document, which reproduce your problem. – Zarko Mar 22 at 9:45

You can use the figure* environment instead to span the figure over both columns.


text:
# Matter content of $\mathcal{N}=4$ SYM

I've always heard it said that the matter content of $\mathcal{N} = 4$ Super-Yang-Mills theory is uniquely fixed by supersymmetry, but I have never quite understood why this must be so.

Could anyone provide a simple watered-down explanation for why this must be the case?

Existence of supersymmetry in a theory implies that all fields must occur in supermultiplets. Let us now try to figure out what the field content of an ${\cal N} = 4$ SYM could possibly be.

Now, suppose the lowest helicity in a supermultiplet is $h$. For massless representations, the highest helicity in the multiplet is then $h + \frac{1}{2}{\cal N} = h+2$. Now, note that we are interested in a field theory, i.e. with no gravity. We must therefore have no fields with helicities $\pm\frac{3}{2}$ and $\pm2$. Thus, $h \geq -1$ and $h+2\leq+1 \implies h\leq-1$. The two inequalities imply that only one choice of $h$ is allowed, namely $h=-1$.

Thus, there is a unique ${\cal N}=4$ field theory, namely one with lowest helicity $h=-1$ in the supermultiplet. Now, let us count the number of states here. Out of the $4{\cal N} = 16$ supercharges, 8 identically vanish on massless representations. Out of the remaining 8, 4 are raising and 4 are lowering operators. Let us use the 4 raising operators on the $h=-1$ state to create the rest of the multiplet.

$1$ state with $h=-1$

${4\choose 1}=4$ states with $h=-1+\frac{1}{2} = -\frac{1}{2}$.

${4\choose 2}=6$ states with $h=-1 + 2\frac{1}{2}=0$.

${4\choose 3}=4$ states with $h=-1 + 3\frac{1}{2}=+\frac{1}{2}$.

${4\choose 4}=1$ states with $h=-1 + 4\frac{1}{2}=+1$.

The $h=\pm1$ states together forms the gauge boson, the 4 $h=\pm\frac{1}{2}$ states form the 4 Weyl spinors and the 6 $h=0$ states form 6 scalars.

More generally of course, in an ${\cal N}=4$ theory, we may have as many copies of the above field content as we want, say $n$.

Thus, the most general field content of a ${\cal N}=4$ theory is $n$ gauge bosons, $4n$ Weyl spinors and $6n$ scalars. The $n$ gauge bosons may together transform in the adjoint of any gauge group such that $\dim G = n$. Since the gauge boson must transform in the adjoint and the spinors and scalars are in the same multiplet, the Weyl spinors and scalars must also transform in the adjoint. The only freedom in the choice of ${\cal N}=4$ theories then, is the gauge group $G$ (In $SU(N)$ theories $n=N^2-1$).


text:
Resistor Wattage Calculator
Some CT's contain a built-in burden resistor. 1-16 of 156 results for "100 amp 3 phase panel" Skip to main search results P3042B3100CU 100-Amp 30-Space 42-Circuit 3-Phase Main Breaker Load Center. This calculator will select the closest standard resistor value, from 1% 5% or 10% standard EIA values, calculates the error, and prints out a table of the standard values for the given tolerance. Calculate Power, Current, Voltage or Resistance. Conclusion So to run a small LED off of 12 volts we need to use a 500 Ohm 1/2 Watt resistor. Standard Resistor Value Calculator: 1%, 5%, 10%. 125 watt resistor (1/8w) or higher is acceptable. Next we calculate the amperage in the circuit: I = V / RT = 12V / 10 Ohms = 1. Power is measured in units called watts. User manuals, specification sheets, CAD drawings and more. Dump loads need to be properly matched to the maximum power output you can expect from your turbine. There are also some capacitors that are color coded. The 3rd band in the case of 4 band resistor band represents the multiplier ( and 4th band in case of 5 band resistor represents the multiplier). Typical sizes for small resistors are 1/8 Watt, 1/4 Watt, 1/2 Watt, 1 Watt, and so on. The calculator does not go to 3 spots after the decimal and therefore, shows 0. Thus, the voltage drop across the resistor is still 120V. 3 Phase Resistor Load Bank , 300KW 400V Programmable DC Electronic Load. When we use LEDs in circuits we always use a series resistor. While often rounding works up to a specific decimal place, we’ve decided that limiting the length of the result to 13 digits would be more favorable to keep the results consistent. 17 dbi - Database independent access layer. 45 amps The above data shows the peak current that will flow in the resistor when the brake transistor turns on. RE: ohms: A multiplier for base resistor values, which are obtained in the next step. 50 watt load. There are special considerations to all elements of the circuit. This calculator can solve other math problems. 6 Each: 100, 1k, 4. 5 band resistor color code calculator; 5 band resistor identification; 50w 8 ohm resistor; 560 ohm 1 watt resistor; 560 ohm 1/2 watt resistor; 5w zener diode; 680pf capacitor code; 8 ohm resistor; 8 ohm resistor color code; a 100n capacitor in parallel with 10n produces; a capacitor blocks dc but allows ac explain; a parallel plate capacitor is. Multiplying amps (water volume) by volts (water pressure) gives you the wattage (the resulting power or energy). Generally, the larger the resistor package, the more power it can dissipate. The Resistor Guide E-Book: The most complete overview about resistors. The silver band on a resistor represents a positive or negative 10% tolerance. Air cored inductor calculator – Build an inductor of any value! Inverted Vee Antenna – Calculate the wire length for an inverted vee antenna. It is not possible to convert watts directly to amps without also knowing voltage or resistance. The voltage flowing in the zener diode of a regulator circuit is a negative voltage or that its electrons flowing. So the resistor needs to be 290? or as close as is available. The problem with using the formulas, like Ohm's Law or Watts = V*V/R is I don't know what the voltage is at the resistor; presumably it isn't 120v at that point in the circuit and it's unlikely a (120 X 120)/20 = 720 watt resistor. The power formula for a circuit is P = VI, where V is in volts and I in amperes. Ohm's Law Calculator. 1ohm 2w resistor. (Example: 450 Volts times 35 milliamps, or. Not precise or professional, but it's been working fine with no blown chips or LED's. For our example, with 10 volts across the resistor, the power will be (10 x 10)/1000 = 0. Calculators include PCB Trace Width, Ohm’s Law, Parallel Resistor and many more. Bosch uses 2. The WWF series wire wound fusible resistors are manufactured to perform as a regular resistor under normal conditions and as a fuse under excessive load. The problem with using the formulas, like Ohm's Law or Watts = V*V/R is I don't know what the voltage is at the resistor; presumably it isn't 120v at that point in the circuit and it's unlikely a (120 X 120)/20 = 720 watt resistor. Some CT's contain a built-in burden resistor. First we need to calculate the difference between the filament light bulb and the LED light bulb in watts: A = The size of the filament light bulb (in watts). Vout = (R2 / (R1 + R2)) * Vin = (4. Enter 100 in the Watts field and 120 in the Voltage field and press Calculate to find the resistance and current. Now, let's use the power equation to calculate the current through the 30W bulb. If you replace your original 40 ohm resistor with two 80 ohm resistors wired in parallel, the voltage across each resistor is the same, because they're wired in parallel. To calculate the failure rate and MTBF of a resistor using the MIL-HDBK-217F failure model, thermistor or variable resistor, enter its parameters in the following table. A resistor has multiple bands of color on its side. Use a resistor rated higher than the displayed power in the box below "Series Resistor", most cases can use a 1/4 watt resistor. To specify the resistor we need to know three things: the energy per stop, the duty cycle and the ohmic value. 4k5Ω plate to plate / 8Ω speaker = 562. Precise, reliable data are key requirements to ensure that faulty devices are rejected, and perfectly good products are not. In this case we're calculating the current across the resistor (which equals the current going into the series-connected LED). Thermistor Calculator component. Certainly, the maximum possible wattage would be the drive hp converted to watts. This changes the resistor calculation a little. The LED - RESISTOR calculator computes the resistor value (ohms) and size (watts) for the desired LED current , device voltage (Vd), and supply voltage (Vs). So the necessary value for the current limiting resistor is 200 Ohms. Farnell at that time were also. They are typically gapped iron core units, similar in appearance to a small transformer, but with only two leads exiting the housing. The voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω): V (V) = I (A) × R (Ω). Details About Heater Blower Motor Resistor For Jeep Grand Cherokee 4 0l 4 7l Ru1061 5014212aa. When the reflected signal makes it back to the amp, the same 3dB of cable loss will reduce the reflected power to 15 watts. Here is the answer to the question:5/8 as percent or how to convert 5/8 to percent. It is better to calculate the amps per resistor lower than required, as the resistance can be lowered later to increase the amps but cannot be done vice versa. 1/4 watt Resistors - available in a wide selection of values. Worst case here would be the 864 ohm resistor. You cannot calculate amp electrical watts from a db measurement ,only acoustic watts. You could use a 1 watt rated resistor, but it would run hot. 50 shipping. Does codes and Watt/Amp conversion. To calculate the dropper resistor value: Rd = 527. So the maximum power dissipated by each 80 ohm resistor is expected to be, Pmax = Vmax^2/R = 20*20/80 = 5 watts. 8 A when connected to 9 V source Resistors above 5 watts are termed as power resistors and are usually available in different construction. I hope this helps, Steve. Generally, the larger the resistor package, the more power it can dissipate. LED PowerSaver. 2mm by 11mm. For our example, with 10 volts across the resistor, the power will be (10 x 10)/1000 = 0. Ohmite’s TAP600 delivers 600 watts of reliable power to a variety of power conditioning, power transmission, and power control applications. The power P in watts (W) is equal to the voltage V in volts (V) times the current I in amps (A): The power P in watts (W) is equal to the squared voltage V in volts (V) divided by the resistance R in ohms (Ω): The power P in watts (W) is equal to the squared current I in amps (A) times the resistance R in ohms (Ω): Ohm's law. Surface mount resistors come in a variety of sizes. 26W (power disipated by resistor) Like cpemma said, you'll need 2W, which is common. Your order may be eligible for Ship to Home, and shipping is free on all online orders of $35. Sounds like 5000 and 20,000 ohms, my best guess. Calculators for Ohms Law. Find many great new & used options and get the best deals for 3x Coaxial Resistor Used Dummy Loads 50 Ohms 100 and 25 watts at the best online prices at eBay! Free shipping for many products!. Uses pulldown menus and a realistic picture of a resistor. They are available as PDF files and Word documents, so feel free to download, edit, print out anything you need. His hard work that was influenced by many others is available to you in a simple calculator. Leds in series: Supply Voltage VOLTS Voltage Drop Across LED VOLTS Desired LED Current MILLIAMPS How many leds connected. The amp would see a VSWR of 2. Volts, Amps, Watts & Ohms Calculator. The calculator does not go to 3 spots after the decimal and therefore, shows 0. The Inverter Drive Supermarket has developed a Dynamic Brake Resistor Calculator to reduce the time required to specify braking resistors for variable-speed drive (VSD) applications. If you have an initial 4. If the resistors available with wattage rating of ½ , 1 and 2 W, what is the minimum wattage rating can be used for each resistance. And the importance of wattage rating of Resistors. Enter the total voltage supply, Resistance of first load, second load and third load and click calculate. 50pcs 100 Ohm Resistor 1/4 Watt 1 Metal Film Through Hole US SELLER. Just click the colors to calculate tho calculate Ohms. Download Resistor Calculator for LEDs serial and parallel April 7, 2010 December 29, 2015 Software that calculates the resistor value and its power consumption in different LED’s circuit configurations (simple, series o parallel) according to the source voltage, the LED’s voltage and the wanted current value. This is called Ohm's law. The WWF series wire wound fusible resistors are manufactured to perform as a regular resistor under normal conditions and as a fuse under excessive load. Uses pulldown menus and a realistic picture of a resistor. The LED calculator was great for single LEDs--but when you have several, the wizard will help you arrange them in a series or combined series/parallel configuration. Resistance:. More online conversion calculators at Digi-Key. From the outside, all resistors look more or less the same. The Inverter Drive Supermarket has developed a Dynamic Brake Resistor Calculator to reduce the time required to specify braking resistors for variable-speed drive (VSD) applications. This is the new version of the single LED series resistance calculator, good for when you have a single LED and need to know "what resistor should I use with my LED?" This calculator determines that for you. 07 is shown in the Wattage field, then a 0. The bottom one calculates power dissipated in a resistor given the current flowing through it. A resistor can feature up to 6 different color bands. To use the calculator, enter any three known values and press "Calculate" to solve for the others. where: V S is the source voltage, measured in volts (V),; V LED is the voltage drop across the LED, measured in volts (V),; I LED is the current through the LED *, measured in Amperes (Amps/A), and; R is the resistance, measured in Ohms (Ω). 5) Watt resistor should be fine. A 220 Ω resistor has a silver tolerance band. For our example, with 10 volts across the resistor, the power will be (10 x 10)/1000 = 0. In this video, I have shown how to calculate resistor wattage ratings for a circuit. samstechlib. Every resistor has a specific maximum power rating. Delta-Wye resistor networks The Delta-Wye transformation is an extra technique for transforming certain resistor combinations that cannot be handled by the series and parallel equations. We know that the cathode voltage is 2. The formula is simple. Your resistor didn't drift. MONTHLY NEWSLETTER. Also, the slope of the derating can be used to calculate an equivalent thermal resistance in degrees C per watt. This means that some results will be rounded to avoid the numbers getting too long. An additional white band indicates that the resistor is fusible. More online conversion calculators at Digi-Key. For this task, use the Resistor Value Calculator. Physics Calculate the kinetic energy that the earth has because of (a) its rotation about its own axis and (b) its motion around the sun. To calculate the right size of the resistor you need the characteristic data of the load cycle: brake time or duty cycle and the total cycle time. Some CT's contain a built-in burden resistor. Ohm's law formula. A smaller resistor will give a higher speed because of smaller RC delay, and a larger resistor will give lower power consumption. Higher wattage resistors will also work. To buy more than one, enter the quantity you would like to purchase. How to Convert Volts to Watts. Quantization errors in resistor values are inherent to Javascript. 1 Watt Wire Wound High Precision Axial Resistor. The first value to determine is the maximum current: P_{Rating}=I_{Max}^{2}*R_{Nominal} Resistors always have a wattage rating and obviously have a nominal. Question: Once I have these values, how do I calculate the required wattage of the resistors R1 and R2?. It is equivalent to one joule per second (1 J/s), or in electrical units, one volt ampere (1 V·A). I start with a large value, and decrease it until the thing lights up well enough to see, but not as much as when straight power is applied. 5 Watt Resistor - 7. Range and Path Loss Another key consideration is the issue of range. Ok, I'm seriously contemplating this build as a science project of sorts. The parallel resistor calculator has two different modes. Experiment with the voltage drop and Ohm's Law calculators, or explore hundreds of other calculators. The Resistor Color Code Calculator decodes and identifies a value and tolerance of 4 band wire wound resistors. Ohmite 600 Watt Heat Sinkable Planar - TAP600 Resistor Series. They are typically gapped iron core units, similar in appearance to a small transformer, but with only two leads exiting the housing. Like before, the maximum voltage is expected to be 20 volts. I can see no way based on size of resistor or the one lead where this could occur Any inputs or. 60A 750V DC Mobile Load Bank , Intelligent Steel Diesel Generator Load Bank 1500KW Resistive Load Bank CE Certificate With Over Load Protection Alarm. If the CT is rated in Volts per Amp (for example 0. We sell raw speaker drivers (tweeters, woofers, subwoofer, midrange drivers, full range drivers), speaker kits, amplifiers, capacitors, resistors, and inductors. Step 1 - subtract LED voltage from supply voltage. Just need 1 or 2 resistors? No problem! Vetco offers a wide selection of values and sizes, all available in quantities starting from 1 resistor! Type: Metal Film Resistor Tolerance: 5% Size: 1/4 Watt Value: 33KΩ (Ohm) QTY: 1 Resistor. The four variables involved in a two-resistor voltage divider are input voltage, output voltage, resistance 1, and resistance 2. (Example: 450 Volts times 35. 7V (for a red LED) = 10. Calculate the resistance and wattage value for a series voltage dropping resistor. This simple and accurate calculator for your iPhone or iPad, will help you determine the value of any SMD resistor. The formula is simple. Resistance:. A 10 K resistor with a 20% tolerance could actually be anything between 8 K and 12 K. Volts to Watts Calculator It is used to convert the voltage in volts (V) to the power in watts (W) using the current in amps (A). Providing energy efficient and quality LED lightings to businesses. If you want a power of +7 dBm from a 50 ohm source into a 50 ohm load, place a 50 ohm resistor across the source and using a high impedance scope probe you need to measure 1. You may manually enter the the voltage and resistance. The equation for power is: Let's say you are using the LED above with a supply voltage of 12V, an LED forward voltage of 3. If the power rating of a resistor is too low for a par- ticular circuit, it will get hot and burn out, sometimes quickly and other times gradually, depending on how much lower. However, using 50 watts forward power and 30 watts reverse power to calculate VSWR, we end up with a VSWR of 7. Find the power dissipated by each resistor and note whether the power delivered is equal to the dissipated d. 2 Amp ; Now that we know the amperage for the circuit (remember the amperage does not change in a series circuit) we can calculate what the voltage drops across each resistor is using Ohm's Law (V = I x R). Ohm's law formula. Equating acoustic watts from a db measurement to electrical watts in an amp is wrong. W s = desired input power to speaker, in watts. Calculate the resistance and wattage value for a series voltage dropping resistor. How to calculate required wattage. Fill in any two inputs, and one output will display the result. Resistor Series. There are special considerations to all elements of the circuit. This means that some results will be rounded to avoid the numbers getting too long. When the resistor body surface is large enough, as in large wattage resistors, the resistance value, tolerance, and wattage are usually printed on the body of the resistor. Choosing a common resistor size with a value greater than 288 ohms, I selected a 390 ohm metal resistor rated at 0. 8 A when connected to 9 V source Resistors above 5 watts are termed as power resistors and are usually available in different construction. = − + where (capital gamma) is the Reflection coefficient, is the impedance of the source, is the impedance of the load. The light bulb acts like a resistor, RA, with resistance equal to 10Ω. Every resistor has a specific maximum power rating. 5 ohms = 19360 Watts wow !. Passive first order high pass filter. 9/1 means you need about a 0. What size wattage resistor do I need for this project? Does resistor wattage matter in this case? (Wiring schematic picture included!) 14. I would recommend a 1. 4k5Ω plate to plate / 8Ω speaker = 562. Amplifier power: 80 watts continuous average power @ 4 ohms (2 channels driven, THD 0. A smaller resistor will give a higher speed because of smaller RC delay, and a larger resistor will give lower power consumption. For a meter calibrated to 200 Amps full scale deflection, the meter will indicate that 200 Amps is flowing through the shunt when the meter reads 200 Amps. 02 Amps x 0. Start by selecting the type of current which can either be the direct current (DC) or Alternating current (AC) single phase/ three phase. Each of my expamples consists of 100k 1/4 watt Resistors. L-C Filter Equations - Formulas and web calculator. In that case, the 30-ohm resistor will drop a bit less than 1% of the voltage -- the light bulb will drop 11. ›› Definition: Ohm. Several common LED connections are shown in the drawing below the calculator. 8 A when connected to 9 V source Resistors above 5 watts are termed as power resistors and are usually available in different construction. Power in watts is calculated by multiplying the square root of three by the power factor, the current in amps, and the line-to-line RMs voltage in volts. Designing the Right Resistor for Your Product. The voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω): V (V) = I (A) × R (Ω). Top Rated Seller Top Rated Seller. 8 ⨯ 3 ⨯ 110 = 264 watts. S P O N S J O 2 R E B. 5% is common. To buy more than one, enter the quantity you would like to purchase. We've made it even easier for you to calculate the value of this resitor with our LED calculator below. MULTIPLY the voltage you read on pin THREE earlier by the reading you just obtained from the 1-ohm resistor. Ch25 By Zubair Saif Issuu Electromagnetism Ap Multiplechoiceanswers2011 1 Practice Exam 2 Midterm 1 40 mf a 60 mf capacitor charged to 50 v and a 40 mf capacitor charged to 34 v are connected to each other with the two positive plates. = − + where (capital gamma) is the Reflection coefficient, is the impedance of the source, is the impedance of the load. Pasternack's RF Power Conversion Calculator allows you to convert RF input power and RF output power values from variables such as milliwatts (mW), Watts, dBm, dBW, millivolts (mV), and Volts. With LED Resistor Calculator all will be simplest! LED Resistor Calculator will allow you to calculate, with precision, the ideal resistance for the LED you would use, also suggesting how many Watts it should be. The gold band represents a positive or negative 5% tolerance. Explain, step by step, how to calculate the amount of current (I) that will go through each resistor in this parallel circuit, and also the current (I) supplied by the DC voltage source: 36 V 1k5 10k 4k7R1 R2 R3 ﬁle i01237 Question 13 Calculate the total amount of current that the battery must supply to this parallel circuit: 500 Ω 500 Ω 10 V. The Resistor dissipates the regenerated energy in the form of heat. The parallel resistor calculator has two different modes. General Tab The General tab provides the following parameters. Multiplying amps (water volume) by volts (water pressure) gives you the wattage (the resulting power or energy). 2V we know the resistor will have to drop 9. 035 Amperes. For this task, use the Resistor Value Calculator. 75 watts of power; which you might think you can get away with by using a 2 watt resistor. 14928 Oxnard St. What size wattage resistor do I need for this project? Does resistor wattage matter in this case? (Wiring schematic picture included!) 14. To use this tool, simply click on a particular color and number and watch how the actual bands on the resistor illustration change. Now to check the power rating needed for that resistor Watts = VI = 3*. Equations used to calculate the data: V = IR P = VI. Enter resistances into the boxes below and when all values have been input, click on the CALCULATE button and the result will appear in the box below that button. Not precise or professional, but it's been working fine with no blown chips or LED's. 17 dbi - Database independent access layer. This substantially increases gain. Thus, the voltage drop across the resistor is still 120V. * The current through the circuit is constant so I LED is also the current through the resistor. We use rounding at unit-conversion. The four band resistor indicates the first digit for the 1 st band, second digit for the 2 nd band, third digit for 3 rd band (multiplier or power of 10) and the fourth digit for 4 th band represent tolerance of ±5%, ±10%, and ±20%. The voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω): V (V) = I (A) × R (Ω). Calculate Power, Current, Voltage or Resistance. Select the bands to find the resistance value. The four variables involved in a two-resistor voltage divider are input voltage, output voltage, resistance 1, and resistance 2. 125 watt resistor (1/8w) or higher is acceptable. Again, there is a proper formula to calculate the wattage: P = V x I. The adjust current is 80uA so it is good to have at least 1mA in the feedback path. A smaller resistor will give a higher speed because of smaller RC delay, and a larger resistor will give lower power consumption. Table above contains standard values. 7) Pdb (min) = P(peak) / 20 = 279. 4 Band Resistor Color Codes. Calculate the power rating for R1. Sub-mA indicators may be made by driving ultrabright LEDs at very low current. LED calculator. Normally, finding the right resistor for an LED is easy. The board on the left has the bulbs arranged, of course, in parallel, and the board on the right has them in series. I start with a large value, and decrease it until the thing lights up well enough to see, but not as much as when straight power is applied. You need to be sure the wattage (power) rating for your resistor is sufficient for the power being used. To calculate the wattage multiply the current through the resistor by the voltage across it. Appliance Rated Watts Surge Watts Survival Appliances Light bulbs 75 each 75 each. So you know that you need a 200 Ohm resistor. 2000KW Continuous Resistive Reactive Load Bank For Factory Acceptance Test. That is close enough to the 6 volt rating of the load. Products » Pulse Energy Calculator JOULE SCHOOL - Pulse Energy Calculator Pulse Type: Square Wave Pulse Capacitive Charge/Discharge Pulse Exponentially Decaying Pulse. Find the power dissipated by each resistor and note whether the power delivered is equal to the dissipated d. The voltage flowing in the zener diode of a regulator circuit is a negative voltage or that its electrons flowing. More online conversion calculators at Digi-Key. The resistor sits within the ignition circuit wiring. Calculate the power rating for R1. Calculate the active power consumed by the resistor in Watts. Calculators include PCB Trace Width, Ohm’s Law, Parallel Resistor and many more. Enter the LED layout, number of LEDs, supply voltage,the Vf, and If LED values. A1 megohm resistor allows any static charge, whether from the bench through the product and then through the grounded person or operator or vice-versa, to discharge completely over time, typically less than 1 second. Hold the resistor with the gold or silver band to the right and read the resistor from the left to the right. P is the power measured in Watt, I is the current measured in Ampere, V is the voltage measured in Volt; the power dissipated in resistor with voltage of 3 Volt and 0. The following expression provides a straightforward solution to calculate accurately the base resistor of a transistor. Leds in series:. Also the plate to plate Impedance can vary between 3kΩ to 5kΩ with little change to the available power. The power available in an electrical circuit is. We have presented 3 charts below – which are exactly resistor color code charts for 4 band, 5 band and 6 band resistors respectively. 5 AMPs, etc. Your resistor must be able to dissipate the amount of power that needs, otherwise it will be burned. 5 watts) Divide your desired wattage by your plate voltage from step 3. The wattage rating of a resistor just tells you how many volts can be across the resistor times the current flowing through the resistor. Select the waveform. Tolerance: 1%. Finally, you need to determine what wattage the resistor must be. A 2W resistor would work, although I'd go with 5W. Leds in series: Supply Voltage VOLTS Voltage Drop Across LED VOLTS Desired LED Current MILLIAMPS How many leds connected. Too much resistance at the base affects the stability of biasing. Convert watts to volts. The equation is: P = √3 ⨯ PF ⨯ A ⨯ V. Since we separate to calculate, we have to calculate all parameters. Tentukan watt resistor. 1V for AlGaInP, 3. Total length of each 2W resistor is 80mm (over 3") with body size 5mm by 15mm. Color bands are usually found on resistors that have a wattage value of 1/8 to 2 watts; though it is rare, there are some 5 watt resistors that are banded. So the maximum power dissipated by each 80 ohm resistor is expected to be, Pmax = Vmax^2/R = 20*20/80 = 5 watts. Or for a 1. The value of RE affects the base bias resistor values and input impedance. Capacitor options include long lifetime, AEC-Q200 compliance, high moisture resistance, anti-vibration and extremely small case sizes that provide board space savings. Resistors are available with ratings from as low as 1/8 watt to hundreds of watts. This means you still limited to a 1 watt circuit. The unit of energy is the joule, the unit of power is the watt, and the unit of time is the second. This is called Ohm's law. The educational resource for the global engineering community. 4 Example For Fast-mode I2C communication with the following parameters, calculate the pullup resistor value. You will get the results of voltage drops in volts. Bear in mind that pull-up resistor values also affect power dissipation in the circuit, as well as rise and fall times of logic signals; you should consider those effects when choosing a pull-up resistor value. Use this Ohm's Law calculator to easily calculate the power, resistance, voltage, or electrical current, based on two known parameters. Unique Bargains 100W 130 Ohm 5% Fixed Type Wire Wound Resistor 130R 100 Watt. For this we need the Voltage drop across the resistor (VoltageInput - LEDVoltageDrop) and the current limit of the LED. Dynamic Brake Resistors - Full range of Braking Resistors from 500 to 2 Ohms and up to 23kW (Page 1 of 16). Of course one would like to fix or define underlying cause for failure. Custom resistors and resistor network solutions are also available. The value of RE affects the base bias resistor values and input impedance. This way, you can check calculations you've made to see if they are correct and. And the importance of wattage rating of Resistors. For example, a one watt signal at port 1 will result in two quarter-watt signals at ports 2 and 3 (down by -6 dB). Leverage Watlow's growing toolkit of calculators, equations, reference data and more to help design your thermal system. Thi s sensor is used with the Bird model 4421 Precision RF power meter. The Attempt at a Solution. In order to get the vehicle started, the starter sends a higher amperage to the spark plugs when you turn the key in the ignition. After entering all of the required values, the parallel circuit calculator automatically generates the result you need. Power Calculator. In the calculator below, for this example, you type in 80 for the power and 6 for the impedance. Order Ballast Resistor for your vehicle and pick it up in store—make your purchase, find a store near you, and get directions. 50 watt load. This may cause a DC link voltage rise up to a critical level. Resistor selection, based on these ratings and the application, will be covered in section 3. Let's say R1 and R2 are 1/2 watt, and R3 is a 2 watt resistor. Measure out of circuit and tell us about it. When voltage and current are known use R = V/I to calculate the value of the resistor. Just enter 2 known values and the calculator will solve for the others. Details About Heater Blower Motor Resistor For Jeep Grand Cherokee 4 0l 4 7l Ru1061 5014212aa. To dissipate our 120 watts, we could use 3 of the 40 watt resistors, or better still, 3 of the 50 watt resistors, to give us some breathing space. ----- -Stand…. Too much resistance at the base affects the stability of biasing. Enter resistances into the boxes below and when all values have been input, click on the CALCULATE button and the result will appear in the box below that button. Riedon has played an integral role in the updated design and manufacturing process of resistors. Select the first 3 or 4 bands for 20%, 10% or 5% resistors and all 5 bands for precision (2% or less), 5-band resistors. Toll Free 1-866-681-9602 • Local: 905-681-9602 • Fax: 905-631-5777 • Email: [email protected] 5KΩ resistor as our R2 resistor with the R1 resistor being 10KΩ. General Tab The General tab provides the following parameters. Miniature indicator LEDs are normally driven from low voltage DC via a current-limiting resistor. Calculate the resistance value of R1. Its been my understanding the resistor color bands just identify the type and value of a resistor. These resistors can be designed for liquid or air cooled heat sink systems. This means you still limited to a 1 watt circuit. Just enter 2 known values and the calculator will solve for the others. These calculators perform calculations associated with power (wattage). 5 x 24 x 38: It handles 0. Download Resistor Calculator for LEDs serial and parallel April 7, 2010 December 29, 2015 Software that calculates the resistor value and its power consumption in different LED’s circuit configurations (simple, series o parallel) according to the source voltage, the LED’s voltage and the wanted current value. 7) Pdb (min) = P(peak) / 20 = 279. The voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω): V (V) = I (A) × R (Ω). Between J/s and W measurements conversion chart page. Determine Resistor Value From Its Color Code Stripes Have a resistor and not sure of the value? Use our online calculator to determine the resistor value. 8 A when connected to 9 V source Resistors above 5 watts are termed as power resistors and are usually available in different construction. A large 10 Watt 470R resistor or similar value Resistor is placed in series with each Cathode. Those problems are all in the past; the Happy Hippy's Resistor Calculator is here. Custom resistors and resistor network solutions are also available. 1 watt - so a 1/8 watt resistor will be fine. If there is no tolerance band, then find the side that has. Table above contains standard values. You need to be sure the wattage (power) rating for your resistor is sufficient for the power being used. If there is no gold or silver banding, then the color bands will be grouped to the left of center of the body of the resistor. Post Glover Resistors, founded in 1892, has the industrial and utility experience in power resistors to deliver proven solutions for your critical applications. Leds in series: Supply Voltage VOLTS Voltage Drop Across LED VOLTS Desired LED Current MILLIAMPS How many leds connected. It is pretty useful information to know if a resistor will burn out just by the amount of voltage present within a circuit. Van Nuys CA, 91411-2610 FAX: 818-781-2653. 5 Ohm resistor, you can use eight 100 Ohm resistor in parallel. Total length of each 2W resistor is 80mm (over 3") with body size 5mm by 15mm. (in case of 5 band resistor take it as 5th band) Tolerance can be +-. Note: In the diagrams below we are considering the battery to be ideal, no internal resistance and always at a constant 12 volts. There are many different types of resistors. After entering all of the required values, the parallel circuit calculator automatically generates the result you need. 6V, then the difference is so tiny, it's not worth bothering about. Resistors of different power ratings are produced, most commonly from 0. The adjust current is 80uA so it is good to have at least 1mA in the feedback path. Details About Heater Blower Motor Resistor For Jeep Grand Cherokee 4 0l 4 7l Ru1061 5014212aa. Simply by specifying the required impedance in ohms and (optionally) the continuous load in watts, the calculator will search 880 resistor combinations to suggest. See our Capacitor Color Code Calculator. We bring the broadest line of neutral grounding resistor products and the most engineering experience in the industry. Resistor color code calculator. After entering all of the required values, the parallel circuit calculator automatically generates the result you need. If we know the voltage across, and the current through, an unknown resistor, we can find the value of the resistor through Ohm's law. This calculator is based on the Ohms Law Calculator, but takes into consideration the voltage drop from the LED. This is a handy tool to recalculate current if you need to stay. I start with a large value, and decrease it until the thing lights up well enough to see, but not as much as when straight power is applied. Calculate how much power your system needs by entering your setup. If this calculator is used for other 100% DC systems, or if you are using Speeduino code capable of 100% DC, then multiply the Resistor Watts figure by 1. MegaResistors specializes in the design, manufacturing, and application of power resistors. This is true for many materials, over a wide range of voltages and currents, and the resistance and conductance of electronic components made from these materials remains constant. The resistor value is read from the left to right. 1-16 of 156 results for "100 amp 3 phase panel" Skip to main search results P3042B3100CU 100-Amp 30-Space 42-Circuit 3-Phase Main Breaker Load Center. if the spot was red, it would add two after the first number. Ini disebut hukum Ohm. Select the waveform. So an 18ohm resistor rated 1/2 watt or better will drop the voltage the 3V you need at the high end. When a circuit does not exceed the power rating, the resistor works reliably and without fuss for decades. As a test, if you input resistances of 3, 9 and 18 ohms, your answer should be 2 ohms. LED Resistor Calculator. Calculate the resistance and wattage value for a series voltage dropping resistor. Free Ground shipping in the continental US for orders over$200. The PowerFlex Family of Drives can use either the internal dynamic brake resistor option or an externally mounted dynamic brake resistor wired to the drive. We sell raw speaker drivers (tweeters, woofers, subwoofer, midrange drivers, full range drivers), speaker kits, amplifiers, capacitors, resistors, and inductors. It is pretty useful information to know if a resistor will burn out just by the amount of voltage present within a circuit. Calculates capacitor formulas. The LED series/parallel array wizard is available for those of you who need to do calculations involving more than one LED. Convert watts, volts, and amps. The output level to the headphones is continuously adjustable. 02 A current would require a 220 Ω resistor: 5 V - 1. 1ohm 2w resistor. The 1 watt reference for the db measurement is acoustic watts not electrical watts in the amplifier. But when you look for components you find that there are several different types of resistors. The value of the Cathode resistor depends on the type of output valves and the B+ supply. Wiring Frames 0…4 Wire to the DB resistor should be no longer than 10 feet from the drive terminals. Need you to post scematic or link to be sure. Aspects of a high pass filter schematic follow. You may find it helpful to have a calculator with a percent function in the workshop!. For a meter calibrated to 200 Amps full scale deflection, the meter will indicate that 200 Amps is flowing through the shunt when the meter reads 200 Amps. According to Ohm’s law , 5 V passing through a 220 ohm resistor is 0. I usually regard a 20% resistor as acceptable if it is within 25% of its nominal value. 2) = 330 - 66 = 264 ohms?. samstechlib. In general, ultra-bright white LEDs outer plastic sheath becomes transparent colors of these LEDs is higher than the normal operating voltage, such as normal. During the video, we. Calculate the reactive power consumed by the inductor in VARs. through a resistor the higher the power (wattage) rating must be. I am using a 2-resistor voltage divider with R1 = 22KΩ and R2 = 4. Bx: const: Use 'Calculate values' button to evaluate exact values for base resistors. Simple to use Ohm's Law Calculator. It is not possible to convert watts directly to amps without also knowing voltage or resistance. The value of RE affects the base bias resistor values and input impedance. 2:1, +/- 5%. One more thing to consider is the power rating of the resistor. I hope this helps, Steve. Compensators. Number of resistors and their value may vary according to size of the straps, applied voltage, and expected ambient temperature. Ini disebut hukum Ohm. Before using this Dynamic Brake Calculator: Important ! 1, What is the Grid Voltage? 2, What is the horse power of the motor? 3, Is the Drive System with transmission Gears or without Gears? 4, What type is the motor?. From Ohm's law R(resistance)=V(voltage) / I(current) we transform the formula to I =V / R. These calculators perform calculations associated with power (wattage). You may manually enter the the voltage and resistance. Start by selecting the type of current which can either be the direct current (DC) or Alternating current (AC) single phase/ three phase. Example #8: Find the value of unknown resistor which drops 10 V when 25 mA current is flowing through it. Rated Watts is when the item is RUNNING. Calculate the resistance value of R1. Example: if 0. Hi Sir, I want to use 2n3055 as pass transistor in zener diode voltage regulator. 02 A A red LED with a forward voltage of 1. Let us consider the color code for the resistor with the bands BROWN-BLACK-RED-GOLD. Calculate Power, Current, Voltage or Resistance. ›› Definition: Watt. According to Ohm’s law , 5 V passing through a 220 ohm resistor is 0. Question: Once I have these values, how do I calculate the required wattage of the resistors R1 and R2?. Again, there is a proper formula to calculate the wattage: P = V x I. So a 62 ohm 3 watt resistor will drop your B+ around 10 volts. 035 Amperes. The power P in watts (W) is equal to the voltage V in volts (V) times the current I in amps (A):. The power rating of a resistor is measured in watts, and it's usually somewhere between ⅛W (0. The resistor R11 serves two purposes: it is the cathode resistor for the triode, and it is the "R2" resistor in the R1/R2 voltage divider pair of the NFB circuit. You can use the following formula to determine your required wattage. LED RESISTANCE CALCULATOR Nearest higher rated 10% resistor Calculated Resistor Wattage WATTS Safe pick is a resistor with power rating of WATTS. Resistors of different power ratings are produced, most commonly from 0. 4-20mA loops transmit the signal as electrical current (milliamps), but the receiver device with the analog input ‘reads’ the signal as a voltage, whether the signal to be read is analog or HART. Use a 1/8th watt or larger resistor soldered to the anode of the led and connect the +12 to the resistor. It would dissipate 10. Let's say R1 and R2 are 1/2 watt, and R3 is a 2 watt resistor. Each board has three 40-watt bulbs, connected as shown by the resistor circuit painted on it. Certainly, the maximum possible wattage would be the drive hp converted to watts. Does codes and Watt/Amp conversion. 02A, you can see that the Watt rating of the resistor should be at least P=V*I=3. We bring the broadest line of neutral grounding resistor products and the most engineering experience in the industry. The educational resource for the global engineering community. 25 amps) flows through the bulb. Here is the answer to the question:5/8 as percent or how to convert 5/8 to percent. standard value decade for 1% resistors ohms* 10. You can also watch this video where Kevin explains why we always use a series resistor, and explains how to calculate the value of the resistor. Vetco stocks a full selection of 1/4 Watt, 1/2 Watt, 1 Watt, 2 Watt, 5 Watt, 10 Watt and Surface Mount Resistors. 03 watts to kilowatts and higher. 2k (1200) ohm resistor also 1 watt. Kilowatt (kW) — Equal to 1000 watts. General Tab The General tab provides the following parameters. Resistor color code calculator. In addition, experiment with the resistor and Ohm's Law calculator, or explore hundreds of other calculators addressing math, finance, fitness, health, and more. The basic equation for power is:. The heavy duty resis-tor series is rated for 50% duty cycle at 150% motor torque. Resistance: 499 Ohm. Also we need the formula for power which is P(power)=V(voltage) * I(current) As we see we already have the voltage, so we need to find the current. P = power in watts. Kilowatt (kW) — Equal to 1000 watts. 040 R=245ohms. Or for a 1. Most resistors are designed to handle 1/8 W or 1/4 W. Therefore, when there is 50 Amps flowing through the shunt, there is 50 X 0. 35v (voltage across resistor) 4. Example #8: Find the value of unknown resistor which drops 10 V when 25 mA current is flowing through it. If you want a power of +7 dBm from a 50 ohm source into a 50 ohm load, place a 50 ohm resistor across the source and using a high impedance scope probe you need to measure 1. A large 10 Watt 470R resistor or similar value Resistor is placed in series with each Cathode. Best seller in single fixed resistors. Just enter 2 known values and the calculator will solve for the others. If the 4th band is absent the tolerance will be 20%. At that time I had only an analogue meter and a calculator to work with. Series resistor. In practice we can accept a 20% resistor if it is a bit outside this. Almost all leaded resistors that have a power rating of 1 watt or less will come with a color code printed on it. 07 is shown in the Wattage field, then a 0. The last band on a 6 band resistor is the temperature coefficient of the resistor, measured in PPM/C or parts per million per degree Centigrade. ----- -Stand…. 7 = 5597 watts (Rdb = 108. Are you saying that I'm wrong on both drawings, or the second drawing and why? Thanks. Experiment with the voltage drop and Ohm's Law calculators, or explore hundreds of other calculators. 5 for InGaN and 1. Of course the current through a wire is controlled by the impedance- usually we know the impedance and voltage and use the derived formula. The one lead would have to carry approx 1. 5 watt although theoretically a 1 watt resistor should suffice. Dump loads need to be properly matched to the maximum power output you can expect from your turbine. I start with a large value, and decrease it until the thing lights up well enough to see, but not as much as when straight power is applied. We can now calculate the resistance using the formula R=V/I. For more information about resistor color code decoder read HELP or see Reversible color code calculator. As a test, if we enter resistances of 4, 6, and 12 ohms, the answer should be 2 ohms. (example: 15/450 =. Electrical Resistance in Serial and Parallel Networks - Resistors in parallel and serial connections. In WWF series, resistors up to 5W, the resistance value is colour coded with 3 bands plus a tolerance band. So you know that you need a 200 Ohm resistor. This maps the maximum battery voltage to approximately 2. A resistor has multiple bands of color on its side. We explain how the high pass works and how a high pass can be calculated. To calculate the minimum and maximum resistance values, we multiply the resistance value by the tolerance percentage to come up with the following values: Minimum = 750000 - (750000 x 5/100) = 750000 - 37500 = 712500 = 712. In order to calculate the wattage we need to know the voltage and the resistance and Ohm's law. More than 170 pages of content. To prevent overheating - make sure that actual power on each resistor doesn't approach their maximum rated power (usually 0. Resistor watts with PWM This page has been accessed 1,267 times since January 28th, 2017. If there is no tolerance band, then find the side that has. 0008 W 0 dBm. Converting voltage to power measured in watts is easy using a simple Watt's Law formula. In the calculator below, for this example, you type in 80 for the power and 6 for the impedance. 4 Band Resistor Color Codes. One must choose the Pull-Up / Pull-Down resistor value optimally so that it won’t draw excess through the resistor. 51 and Higher Watt Wire Wound High Precision Axial Resistor; Current Sensing/Shunts. That is close enough to the 6 volt rating of the load. How to Convert Volts to Watts. E (voltage) times I (current) = watts. To calculate the right size of the resistor you need the characteristic data of the load cycle: brake time or duty cycle and the total cycle time. In some circumstances, e. The wattage rating of a resistor just tells you how many volts can be across the resistor times the current flowing through the resistor. (in case of 5 band resistor take it as 5th band) Tolerance can be +-. This calculator can determine the resistance of up to 10 resistors in parallel. I = current in amperes. You could use a 1 watt rated resistor, but it would run hot. @Amp Mad Scientist and @ivan H (and others) have told me this is not at all a difficult conversion/ My goal is super-tight bass response. Example #8: Find the value of unknown resistor which drops 10 V when 25 mA current is flowing through it. In addition to a resistance value, measured in ohms, it has a maximum power rating, measured in watts. The rated watts for the resistor needs to be at least 1/10 w, but a more standard number is ¼ watt, thus we can use a quarter watt 280-ohm resistor. For switching applications, a ¼-watt resistor with 5-% tolerance usually works fine. Volts to Watts Calculator It is used to convert the voltage in volts (V) to the power in watts (W) using the current in amps (A). For instance, at 7500 ohms when 120 VAC is commanded on about I=E/R amps (120/7500 = 0. The first mode allows you to calculate the total resistance equivalent to a group of individual resistors in parallel. These charts will be a great study guide to help you master the resistor inside and out, backwards and forwards. When we use LEDs in circuits we always use a series resistor. The more watts a resistor can handle, the larger and more expensive the resistor is. The one lead would have to carry approx 1. A resistor can feature up to 6 different color bands. Multiply the resistance of the component by the current thru it. This calculator uses the power equation $$P = I \times V$$ ~P~ is the power rating of the power tube, ~I~ is the bias current, and ~V~ is the plate voltage of the power tube. BUT if R3 is a 1 watt, then you have a one watt circuit. The wattage of the resistor used for R1 must be greater than the value reported by the calculator. Expert Panel Responses: This is a good question. Equal to 1000 Watt-hours. Leds in series: Supply Voltage VOLTS Voltage Drop Across LED VOLTS Desired LED Current MILLIAMPS How many leds connected.


text:
# Proof Black Scholes Theta

I saw the following proof of theta in a paper I read, and I thought it looked pretty neat. Unfortunately I don't understand the step that they do. This is what they do:

Now, I don't get how they go from $$S_0 n(d_1)\frac{\partial d_1}{\partial t} - Xe^{-rt}n(d_2) \frac{\partial d_2}{\partial t}$$ to $$S_0 n(d1) \frac{\partial (d_1-d_2)}{\partial t}$$. Could anyone explain to me why this is true?

• Consider the relationship of $d_1$ and $d_2$ as well as the relationship of $n(d_1)$ and $n(d_2)$. – Gordon Oct 24 '18 at 17:36
• so $d_2 = d_1 - \sigma \sqrt{T}$, and consequently I thought $n(d_2) = n(d_1 - \sigma \sqrt{T})$. How can I use this to go further? – Keith Oct 24 '18 at 17:50
• Would it help to write out the normal density function? – Keith Oct 24 '18 at 18:00
• Yes, to write out the normal density function. – Gordon Oct 24 '18 at 18:02
• See also this question. – Gordon Oct 24 '18 at 18:10

There is a well known identity for the Black Scholes model: $$S_0 n(d_1)-X e^{-rT} n(d_2) = 0$$ (proof).

Using this allows you to combine these two terms:

$$S_0 n(d_1)\frac{\partial d_1}{\partial t} - Xe^{-rT}n(d_2) \frac{\partial d_2}{\partial t}$$

into

$$S_0 n(d1) (\frac{\partial d_1}{\partial t}-\frac{\partial d_2}{\partial t})$$

or

$$S_0 n(d1) \frac{\partial (d_1-d_2)}{\partial t}$$

Then we use the fact that $$d_1-d_2=\sigma\sqrt{t}$$

Since Black Scholes Theta is for the Black–Scholes option pricing formula, the above step holds true.

For more info, refer page 3 and 4 of this pdf. http://moya.bus.miami.edu/~tsu/jef2008.pdf

• This paper just repeats the equations above with no further explanation. – Alex C Nov 23 '18 at 23:00


text:
Changeset 1115 for trunk/yat

Ignore:
Timestamp:
Feb 21, 2008, 8:20:59 PM (15 years ago)
Message:

Fixes #254 and #295

Location:
trunk/yat
Files:
5 edited

Unmodified
Removed
• trunk/yat/classifier/KNN.h

 r1112 /// @brief Class for Nearest Neigbor Classification. /// /// The template argument Distance should be a class implementing /// The template argument Distance should be a class modelling /// the concept \ref concept_distance. /// The template argument NeigborWeighting should be a class implementing /// The template argument NeigborWeighting should be a class modelling /// the concept \ref concept_neighbor_weighting.
• trunk/yat/classifier/NCC.h

 r1112 /// @brief Class for Nearest Centroid Classification. /// /// The template argument Distance should be a class implementing /// The template argument Distance should be a class modelling /// the concept \ref concept_distance. ///
• trunk/yat/statistics/EuclideanDistance.h

 r1093 /// /// @brief Calculates the Euclidean distance between two points /// stored in 1-dimensional containers. Implements the concept \ref /// concept_distance. /// given by elements of ranges. /// /// This class is modelling the concept \ref concept_distance. /// /// { /** \brief Calculates the Euclidean distance between two ranges. \brief Calculates the Euclidean distance between elements of two ranges. If both ranges are unweighted the distance is calculated as \f$\sqrt{\sum (x_i-y_i)^2 } \f$ If elements of both ranges are unweighted the distance is calculated as \f$\sqrt{\sum (x_i-y_i)^2 } \f$, where \f$x_i \f$ and \f$y_i \f$ are elements of the first and second range, respectively. Else distance is calculated as \f$N \frac{\sum w_xw_y(x-y)^2}{\sum w_xw_y} \f$ If elements of one or both of ranges have weights the distance is calculated as \f$\sqrt{N \sum w_{x,i}w_{y,i}(x_i-y_i)^2/\sum w_{x,i}w_{y,i}} \f$, where \f$N \f$ is the number of elements in the two ranges and \f$w_x \f$ and \f$w_y \f$ are weights for the elements of the first and the second range, respectively. If the elements of one of the two ranges are unweighted, the weights for these elements are set to unity. */ template
• trunk/yat/statistics/PearsonDistance.h

 r1092 /// /// @brief Calculates the %Pearson correlation distance between two points stored in 1-dimensional containers. Implements the concept \ref concept_distance. /// @brief Calculates the %Pearson correlation distance between two points given by elements of ranges. /// /// This class is modelling the concept \ref concept_distance. /// struct PearsonDistance { /// /// @brief Calculates the %Pearson correlation distance between two ranges. /// /** \brief Calculates the %Pearson correlation distance between elements of two ranges. If elements of both ranges are unweighted the distance is calculated as \f$1-\mbox{C}(x,y) \f$, where \f$x \f$ and \f$y \f$ are the two points and C is the %Pearson correlation. If elements of one or both of ranges have weights the distance is calculated as \f$1-[\sum w_{x,i}w_{y,i}(x_i-y_i)^2/(\sum w_{x,i}w_{y,i}(x_i-m_x)^2\sum w_{x,i}w_{y,i}(y_i-m_y)^2)] \f$, where and \f$w_x \f$ and \f$w_y \f$ are weights for the elements of the first and the second range, respectively, and \f$m_x=\sum w_{x,i}w_{y,i}x_i/\sum w_{x,i}w_{y,i} \f$ and correspondingly for \f$m_y \f$.  If the elements of one of the two ranges are unweighted, the weights for these elements are set to unity. */ template double operator()
• trunk/yat/utility/iterator_traits.h

 r1092 /** Struct to be used to make compile-time decision that Iterator is weighted. Some algorithms come in also in a weighted version in weighted. Some algorithms come also in a weighted version and this tag could be used to decide on using them (rather than unweighted cousin). the corresponding unweighted algorithm). */ struct weighted_iterator_tag {}; /** \brief traits to make unweighted iterator work in as a weighted \brief traits to make unweighted iterator work as in a weighted This class must be implemented for every iterator that can be weighted.
Note: See TracChangeset for help on using the changeset viewer.


text:
TutorMe homepage
Subjects
PRICING
COURSES
Start Free Trial
Nilay A.
Computer Science Tutor
Tutor Satisfaction Guarantee
Physics (Waves and Optics)
TutorMe
Question:

Using diffraction seems to be a useful technique for measuring size of small object. Is there a lower limit for size of objects that can be measured this way?

Nilay A.

We know that: $$\sin(\theta) = m\lambda/a$$ Since $$\sin(\theta) \leq 1 \implies \lambda \leq a$$ So you cant measure the size of the object shorter than the wavelength of the light.

Python Programming
TutorMe
Question:

What will be output of following program ? b = [2,5,6,7,8,9,10,23,15] b[::2] = 11,22,33,44,55,66 print(b)

Nilay A.

It will give ValueError since we are attempting to assign sequence of size 6 go extended slice of size 5.

C Programming
TutorMe
Question:

What is Dangling Pointer?

Nilay A.

Dangling Pointer is a pointer that doesn't point to a valid memory location. They arise when an object is deleted or de-allocated, without modifying the value to the pointer, so that the pointer still points to the memory location of the deallocated memory. Following is an example: int *ptr = (int *)malloc(sizeof(int)) free(ptr) In this example "ptr" becomes a dangling pointer after freeing it and any operation on "ptr" now like *(value of) or &(address of) becomes invalid.

Send a message explaining your
needs and Nilay will reply soon.
Contact Nilay


text:
## collegegirl89 Group Title please help!!!! i need to know the horizontal tangents of sin(25x) and the vertical tangents of cos(25x). I got answers of 0 and pi/25 and 25pi/2 and 75pi/2, but my online hw says that theyre wrong one year ago one year ago

1. richyw

$$f(x)=\cos(25x)$$ has no vertical tangent lines, are you in cartesian coordinates?

2. richyw

for the first one you can just take the derivative and set it equal to zero. so $\frac{d}{dx}(\sin25x)=\cos (25x)\cdot\frac{d}{dx}25x=25\cos (25x)$

3. collegegirl89

yeah the interval is from 0 to 2pi

4. collegegirl89

ahh im confused

5. collegegirl89

i thought that cos(25x), when set equal to 0 yielded pi/50 and 3pi/50


text:
# Normalize and expand rules

This section will cover the rules that are applied when normalizing and/or expanding functions. But before we start on
that, take a look at the example below which explains shortly how functions are handled internally within MUMIE.

Example:
Take the following function: $$x^4 \cdot (3 + 2)$$. To input the function into MUMIE, you would type the following:
x^4*(3+2), which in turn could be graphically displayed as the image below.

MUMIE uses the following terminology regarding the tree you see above.

• node referring to a box in the tree
• operation every node, together with its children, can be referred to as an operation.
The example above consists of the following operations
• Multiplication Operation (or simply MultiplicationOp)
• PowerOp,
• VariableOp and
• NumberOp.

Operations can be combined together to make more complex operations. The formula used above can therefor also be referred to as an operation.

Every node has the following properties:

• factor
• exponent

and based on the type, possibly a:

• base (if it is a NumberOp)
• identifier (if it is a VariableOp)

Keeping this in our mind, we can take a look at the rules being applied when normalizing and/or expanding functions.
When normalizing/expanding, all rules will be applied until a stable state of the function has been reached, resulting in a normalized/expanded function. The rules for
normalization and expanding
below (showing the Class name of the Java-code in brackets), along with several examples for each rule.

# Rules for normalizing functions

## Collapse factors of a variable (NormalizeMultRule)

$$3 \cdot 5 \cdot x$$ $$\Rightarrow$$ $$15x$$
$$3 \cdot 5 \cdot x + 2 \cdot 4 \cdot y + 2 \cdot 3$$ $$\Rightarrow$$ $$15x+8y+2 \cdot 3$$

## Collapse multiplications and additions (CollapseEqualOpsRule)

$$4+(3-4)$$ $$\Rightarrow$$ $$4+3-4$$
$$3-(-4+x)$$ $$\Rightarrow$$ $$3+4-x$$

For multiplication:

$$3 \cdot (4 \cdot 9 \cdot x)$$ $$\Rightarrow$$ $$3 \cdot 4 \cdot 9 \cdot x$$
$$\frac{3}{\frac{1}{4} \cdot x}$$ $$\Rightarrow$$ $$\frac{3 \cdot 4}{x \cdot 1}$$

## Collapse powers of i (CollapsePowerOfIRule)

$$i^2$$ $$\Rightarrow$$ $$-1$$
$$i^8$$ $$\Rightarrow$$ $$1$$
$$i^{-7}$$ $$\Rightarrow$$ $$i$$

## Evaluate expressions involving only numbers (PropagateConstantsRule)

$$12.0+2.0^{3.0} \cdot 3$$ $$\Rightarrow$$ $$36$$

## Evaluate expressions having zero as a factor (RemoveZeroMultRule)

$$0 \cdot 3$$ $$\Rightarrow$$ $$0$$
$$0 \cdot x$$ $$\Rightarrow$$ $$0$$

## Evaluate powers with zero as exponent (RemoveZeroExponentRule)

$$2x^{0}$$ $$\Rightarrow$$ $$2 \cdot 1$$

$$y+2x + z - x$$ $$\Rightarrow$$ $$y+x+z$$

## Collapse equal children belonging to multiplication operations (SummarizeEqualMultChildrenRule)

$$x \cdot y \cdot x$$ $$\Rightarrow$$ $$x^2 \cdot y$$
$$y \cdot x^2 \cdot z \cdot x^{-1}$$ $$\Rightarrow$$ $$y \cdot x \cdot z$$

## Remove neutral elements (RemoveNeutralElementRule)

Only handles the following three cases

$$x \cdot 1$$ $$\Rightarrow$$ $$x$$
$$x \cdot -1$$ $$\Rightarrow$$ $$-x$$
$$x + 0$$ $$\Rightarrow$$ $$x$$

## Collapse powers (CollapsePowerRule)

Implements the following two rules:

$$(a^b)^c$$ $$\Rightarrow$$ $$a^{bc}$$
$$e^x$$ $$\Rightarrow$$ $$\exp(x)$$

## Collapse powers when rational (CollapseRationalPowerRule)

If the node is a PowerOp with a rational exponent and the denominator of the exponent is n != 1. An n-th root node will be added as parent and the child will get the numerator as exponent.

$$x^{\frac{3}{2}}$$ $$\Rightarrow$$ $$\sqrt{x^3}$$

## Simplify constants of single nodes (NormalizeConstantRule)

Sets exponent to $$1$$ and factor to $$+/- 1$$ and calculates its base.

$$(-2)^3$$ $$\Rightarrow$$ $$-8$$

## Collapse function nodes that have their inverse function as child (CollapseInverseFunctionRule)

This rule only works on functions that have an inverse function defined.

$$\cos(\arccos(x))$$ $$\Rightarrow$$ $$x$$
$$\ln(\exp(x))$$ $$\Rightarrow$$ $$x$$

## Collapse function nodes for powers and n-roots (CollapseNrtRule)

This is a special case of the above rule.

$$\sqrt{x^2}$$ $$\Rightarrow$$ $$\vert x \vert$$

## Symmetry of elementary functions (HandleFunctionSymmetryRule)

Currently only applies to the following functions: @abs, acos, asin, atan, cos, cosh, n-root (for uneven n), sinh, sin and tan@. The rule is dependent on whether the function is symmetric or antisymmetric.

$$\sin(-x)$$ $$\Rightarrow$$ $$-\sin(x)$$
$$\vert -x \vert$$ $$\Rightarrow$$ $$\vert x \vert$$

$$3 \cdot (-x + 4)$$ $$\Rightarrow$$ $$-3x + 12$$

# Rules for expanding functions

## Distributive law (ExpandProductRule)

$$4 \cdot (-b-3)$$ $$\Rightarrow$$ $$4 \cdot (-b) + 4 \cdot (-3)$$

## Expand data in single node (ExpandInternalDataRule)

$$-x^6$$ $$\Rightarrow$$ $$-1 \cdot x^6$$

## Expands a power of products (ExpandPowerRule)

$$(2 \cdot x)^4$$ $$\Rightarrow$$ $$2^4 \cdot x^4$$

## Expands a power of sums (ExpandPowerOfSumRule)

$$(2+x)^4$$ $$\Rightarrow$$ $$(2+x) \cdot (2+x) \cdot (2+x) \cdot (2+x)$$


text:
# Question #ef30e

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

8
Gary P. Share
Oct 27, 2017

Socratic is full with smart students, teachers, retired teachers and more. I am not sure how they manage their times to do that but I think they are willing to help others so they make sure to spend at least 2 hours on the site.

For me, I tried to answer at least 5 questions each day. I love doing that because I love when people are helping me too.

Honestly, I have a lot of assignments too and I consider Socratic as a "Life Saver" for me. The way they helped users with their questions is unbelievable, as you can see :) So whenever, I am not sure about my work, I just post it here to see if I was on the right track.

Listen, if you really want to help others you can do that easily. You have 24 hours, you can give the site at least 20 minutes :)

Best of luck!

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

5
Oct 26, 2017

Some thoughts below:

#### Explanation:

I can't speak for anyone else who contributes, but I can certainly chime in on my contributing experience.

First off, I'm retired. Gone are the days of toiling away for the better part of a day engaged in either making money (i.e. working) or formal learning (i.e. school). My days are mine to do with as I please. It pleases me to have been a part of Socratic and to continue to do so.

There are a few reasons I've started and then continued sharing answers on Socratic for the roughly $1 \frac{1}{2}$ years I've been doing this - stave off boredom, intellectual curiosity, the challenge of answering new and diverse problems, etc. Now I do it because it's part of my morning routine - I wake up, check email, hit social and news media, and then settle in to hang out on Socratic for anywhere between a half-hour to an hour. Sometimes I don't make it here and sometimes I spend more than that, but on average that's my routine.

I look for questions that get me thinking or that simply asked to be answered, like this one did.

I think I can speak for most, if not all, contributors in saying that our involvement with Socratic is a mixture of personal pride, a desire to help others, a means to find personal satisfaction, and in the end something we enjoy doing.

I hope you continue to find Socratic useful!

• 8 minutes ago
• 8 minutes ago
• 8 minutes ago
• 9 minutes ago
• 2 minutes ago
• 2 minutes ago
• 5 minutes ago
• 5 minutes ago
• 5 minutes ago
• 6 minutes ago
• 8 minutes ago
• 8 minutes ago
• 8 minutes ago
• 9 minutes ago


text:
# Simplicial space

A topological space $X$ equipped with a covering by topological simplices (called a triangulation) such that the faces of every simplex belong to the triangulation, the intersection of any two simplices is a face of each (possibly empty), and a subset $F\subset X$ is closed if and only if its intersection with every simplex is closed. Every simplicial space is a cellular space. The specification of a triangulation is equivalent to the specification of a homeomorphism $|S|\to X$, where $|S|$ is the geometric realization of some simplicial complex. Simplicial spaces are also called simplicial complexes or simplicial decompositions. Simplicial spaces are the objects of a category whose morphisms $X\to Y$ are mappings such that every simplex of the triangulation of $X$ is mapped linearly onto some simplex of the triangulation of $Y$. The morphisms are also called simplicial mappings.


text:
Talk:Probability distribution

WikiProject Mathematics (Rated B-class, Top-importance)
This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of Mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Mathematics rating:
 B Class
 Top Importance
Field: Probability and statistics
One of the 500 most frequently viewed mathematics articles.
WikiProject Statistics (Rated C-class, Top-importance)

This article is within the scope of the WikiProject Statistics, a collaborative effort to improve the coverage of statistics on Wikipedia. If you would like to participate, please visit the project page or join the discussion.

C  This article has been rated as C-Class on the quality scale.
Top  This article has been rated as Top-importance on the importance scale.

"random variable may be attributed to a function defined on a state space equipped with a probability distribution that assigns a probability to every subset ... of its state space..." A function defined on a state space should assign something to points of the state space. If it assigns something to sets, it is rather a SET FUNCTION. Also, if the state space is already equipped with a probability distribution, what is the role of the random variable?

"A random variable then defines a probability measure on the sample space by assigning a subset of the sample space the probability of its inverse image in the state space." Really? The two states are swapped here. On the sample space a measure is given from the beginning; on the state space it appears due to the random variable.

"In other words the probability distribution of a random variable is the push forward measure of the probability distribution on the state space." I do not understand this phrase; once again, on which space the measure is given from the beginning? Boris Tsirelson (talk) 16:03, 12 December 2008 (UTC)

Organization of the article: subsection Terminology etc

Perhaps subsection Terminology with its current content is superfluous. Repetition of discrete vs continuous distribution seems confusing (the reader could think he overlooked sth he didn't). The notion of support should appear in the article on measures. Measure, probability and possibly a few other concepts should be referenced at the bottom of the article. More thoughts are needed about organization of the vast legion of important links to related articles.

As a continuous counterpart of formula for probability distribution should be used that with integral using density function (since resembles discrete version very well - just think of density as discrete histogram with dense set of values). After presenting discrete and absolutely continuous distributions in separate sections, there should appear the third section unifying both into the general theory with formula using Lebesgue integral w.r.t. axiomatic probability measure P (this formula which is now horribly serving as definition in the special case of absolute continuous random variable - inacceptable for general purpose encyclopedia). Then some properties, examples and graphs should follow (independently of famous and important distributions described in dedicated articles). Compare e.g. with some good stylistic and logistic ideas applied to the article on expected value. --Megaloxantha (talk) 02:37, 31 December 2008 (UTC)

New "Some Properties" section

Can we do something sensible about the stuff presently in this section, which says:

• The probability density function of the sum of two independent random variables is the convolution of each of their density functions.
• The probability density function of the difference of two random variables is the cross-correlation of each of their density functions.

In the first bullet point, there is a need to say this for general distributions, not just those which have densities ...unfortunately the article on convolution does not seem to give a sensible formula in terms of cumulative distribution functions. In the second bullet point, there is again the problem of dealing with general distributions but, in addition, the use of the word "cross-correlation" would need to be given the interpretation in the article pointed-to, which is very different from the common one in statistics.

Melcombe (talk) 10:38, 31 December 2008 (UTC)

Proposal to archive discussion

Given that this article has had a major revamp, much of the old discussion is irrelevant to the present content. I have reordered the threads a little to put newer stuff towards the end, but I am suggesting that all the stuff now before the section headed "Lead is confusing" be archived. Any thoughts? Melcombe (talk) 12:15, 31 December 2008 (UTC)

Discussion archived as above. Melcombe (talk) 14:21, 20 May 2009 (UTC)

Observation Space

In the formal definition, we have:

"A random variable is defined as a measurable function X from a probability space ${\displaystyle \scriptstyle (\Omega ,{\mathcal {F}},\operatorname {P} )}$ to its observation space ${\displaystyle \scriptstyle ({\mathcal {X}},{\mathcal {A}})}$."

Can we have someone put up a definition of the "observation space"? I'd do it myself but I'm not able enough. --WestwoodMatt (talk) 15:41, 20 March 2010 (UTC)

Formally, it is just a measurable space. Informally, it is the set of all possible values (or a larger set, if more convenient). I also wonder, is "observation space" a standard word, a neologism, or what?Boris Tsirelson (talk) 16:30, 20 March 2010 (UTC)
I'm assuming it's the same thing as the image of ${\displaystyle X}$. But I'm not used to coming at this from the direction of defining the image as a measurable space - the only treatments I'm familiar with regard the image of ${\displaystyle X}$ as just being a subset of ${\displaystyle \mathbb {R} }$. Hence I'm slightly out of my depth, and although I could work through it myself step by step, I'd be unsure as to whether I'd done it right - I'm new to measure theory. --WestwoodMatt (talk) 23:33, 20 March 2010 (UTC)
"Observation space" is used sometimes, see for example here. I did not find the definition, but probably it means the codomain, not just the image. Boris Tsirelson (talk) 07:01, 21 March 2010 (UTC)
An explanation added; please look now. Boris Tsirelson (talk) 10:13, 21 March 2010 (UTC)
I suspect "Observation space" is not standard in the literature, and should be omitted. At least as a PhD student in Stochastic Analysis with decent background in probability and measure theory, I've never seen used before. -- Some random passerby
Also I, an old professor-probabilist, did not see it before (that is before 21 March 2010). Probably, for now it is used mostly by non-mathematicians. But does it mean that it should be omitted? Boris Tsirelson (talk)
I think that the use of non-standard terminology is unfortunate because it makes it harder to read and understand. Especially so in definitions. I also think measure-theoretic definitions are mostly of interest to mathematicians, and thus that terminology should be taken from there. -- The same random passerby.

See also Wikipedia talk:WikiProject Mathematics#Codomain of a random variable: observation space?. Boris Tsirelson (talk) 16:50, 27 March 2010 (UTC)

The term seems self-explanatory when used the way it's used in the article. Someone used the word "unfortunate" above without rigorously defining it. I don't have a problem with that. Michael Hardy (talk) 18:50, 27 March 2010 (UTC)

When you're in a section called "formal definition" it is necessary to define stuff down to this level. Okay then, so although I can make a stab at defining "unfortunate" to a no-mathematically-inclined person (it describes an observation of a random variable whose outcome is contrary to the desires of one's motivational consciousness) I would not be able (in this context) to determine rigorously what an "observation space" is. When something is described as "self-explanatory" I always suspect that this is because the person so describing it lacks the ability to define it. As a logician I can not accept this as an answer. And as a statistician (i.e. I'm not one, I'm just learning this stuff as I go along) I don't understand what an "observation space" is in the terms of the mathematical objects that a probability space is defined in. --WestwoodMatt (talk) 21:35, 27 March 2010 (UTC)
Formal definitions are supposed to be formal. Also, adding definitions not used in the literature is probably a breach of the "no original research" criteria for wikipedia articles.

Enough is enough. Observation space is gone.

Add "mode", "tail", "inflection", etc. to terminology?

Shouldn't the basic terminology used to discuss/describe a distribution be included here? It would not only fill out the basic presentation of the material but also provide an anchor for references to such terms in other articles. Jojalozzo 03:02, 25 July 2011 (UTC)

Strange terminology

As far as I know, "probability distribution" is, in general, a probability measure (rather than this or that function). In some (but not all) cases it can be described by a cumulative distribution function. Sometimes also by the probability mass function; sometimes also by the probability density function. But the lead says "a probability mass, probability density, or probability distribution is a function..." Or is it meant that a measure is also a kind of function (namely, a set function)? But no, this is not written in the sections. Boris Tsirelson (talk) 05:57, 2 July 2012 (UTC)

I have rewritten the lead to try to overcome this problem. But the rest of the article is extremely short of anything understandable about probability measure. Melcombe (talk) 19:20, 3 July 2012 (UTC)
Nice! Much better than before. (But it would be enough, to link "probability measure" in the lead only once.) Boris Tsirelson (talk) 21:09, 3 July 2012 (UTC)

Normal distribution

Why does this article refer to the Gaussian distribution as "the most important distribution"? Isn't this kind of arbitrary? — Preceding unsigned comment added by 2607:4000:200:13:1A03:73FF:FEB3:B07C (talk) 05:46, 27 August 2012 (UTC)

Good question but no it's not arbitrary: there's a theorem somewhere that says that given a large enough sample size, all distributions tend towards the Gaussian in the limit. --Matt Westwood 09:46, 27 August 2012 (UTC)
A quote:
"Gaussian random variables and processes always played a central role in the probability theory and statistics. The modern theory of Gaussian measures combines methods from probability theory, analysis, geometry and topology and is closely connected with diverse applications in functional analysis, statistical physics, quantum field theory, financial mathematics and other areas."
R. Latala, "On some inequalities for Gaussian measures". Proceedings of the International Congress of Mathematicians (2002), 813-822. arXiv:math.PR/0304343.
Boris Tsirelson (talk) 12:41, 27 August 2012 (UTC)
An example: The normal distribution in Rn is the unique (up to scaling) rotation-invariant probability measure with independent components. This purely mathematical result is fundamental to the Kinetic theory of gases. --Rainald62 (talk) 21:36, 29 April 2013 (UTC)
Yes... You mean Maxwell–Boltzmann distribution. Boris Tsirelson (talk) 05:49, 30 April 2013 (UTC)

generic statistical distributions (especially sample distributions)

Right now there seem to be somewhat strange redirects. What article should I link to for a plain old distribution of occurrences as observed in a finite sample?

Nanite (talk) 18:45, 21 January 2014 (UTC)

(Non-)Zero Probabilities for Continuous random variables

I believe "In contrast, when a random variable takes values from a continuum, probabilities can be nonzero only if they refer to intervals" is incorrect. Imagine a random variable whose image is [0,1]. Let the point 1 have a 50% chance of occurring, and the rest of the probability mass is uniformly distributed amongst [0,1). Is there anything wrong with this counter-example? Note that obviously this counter-example extends to letting any finite number of points of the image of a continuous random variable have non-zero probability. 38.88.227.194 (talk) 17:23, 23 September 2014 (UTC)

Right. But that phrase occurs in Introduction, and probably is not meant to be a theorem. Maybe "In contrast, when a random variable takes values from a continuum then, typically, probabilities can be nonzero only if they refer to intervals"? Boris Tsirelson (talk) 20:23, 23 September 2014 (UTC)

Probability in function spaces

I feel that this article is incomplete because it deals only with 'random variables' (scalar or not). However, the notion of a 'random element' can be applied to any set. Specifically, a probability measure on a functional space is a well defined concept under the Kolmogorov measure theoretic point of view. Nevertheless, there are several items on the article that does not apply easly to the case of random functions. For exemple, the concept of a probability density for random functions does not exist ([1]); the concept of cumulative distribution function is replaced, in most presentations, by a infinite hierarchy of cumulative distribution functions; etc. Crodrigue1 (talk) 21:36, 12 October 2016 (UTC)

True. This is shortly mentioned in "Kolmogorov definition" section. This is more often called "probability measure" than "probability distribution". And, specifically for function spaces, this is usually treated in "Random processes". Boris Tsirelson (talk) 06:40, 13 October 2016 (UTC)
• ^ Novikov, 1965; Functionals and the random force method in turbulence theory; Soviet Physics JETP, 20(5), pp. 1290 - 1294


text:
Time and Place: MWF 12:30pm–01:20pm REC 313

Instructor: Arshak Petrosyan

Office Hours: MWF 11:30am-12:30pm, or by appointment, in MATH 610

Course Description: Credit Hours: 3.00. Basic real analysis, limits, continuity, differentiation, and integration. Typically offered Fall.

Textbook:

[B] R. Bartle, The Elements of Real Analysis, Second Edition, John Wiley & Sons, New York, 1975.

Course Outline:

• The algebraic, ordering, and completeness properties of the real numbers. (3 hrs.)
• Topology of Rp. (5 hrs.)
• Sequences in Rp. Convergence and Uniform convergence. Lim Sup and Lim Inf. (5 hrs.)
• Continuous and uniformly continuous functions. sequences of continuous functions. Approximation Theorems. (7 hrs.)
• Differentiation. Mean Value and Taylors Theorem. (3 hrs.)
• The Riemann (Riemann-Stieltjes) Integral. Improper Integrals. (6 hrs.)
• Infinite Series of constant and functions. Absolute and Uniform Convergence. Weierstrass M-Test; Dirichlet and Abel Test. Power Series. Double Series and the Cauchy Product. (8 hrs.)
• Selected Applications of Basic Material (8 hrs.)
• Fourier Series
• Stone-Weierstrass Theorem
• Existence and Uniqueness Theory of Ordinary Differential Equations

(Time should permit to do two of the above applications).

Homework will be collected weekly on Wednesdays (with some exceptions), at the beginning of class. No late homeworks will be accepted, however, the lowest homework score will be dropped. The assignments will be posted here at least one week prior to the due date.

Exams: There will be two midterm exams (evening exams) and a comprehensive final exam (covering all material). The exact times and place will be specified due course.

Final Score = (1/3)FE + (7/30)ME1 + (7/30)ME2 + (1/5)HW,

where where FE, MEi, HW are the scores (in %) for Final Exam, Midterm i, Homework.

Note: If you perform better than average on both midterm exams, you will be given an option of not taking the final exam and your score will be computed by an alternative scheme (to be specified towards the end of the course).

Academic Integrity: As a reminder, all students must comply with Purdue’s policy for academic integrity: