1. Field of the Invention
The present invention relates to voltage and resistance testers and, in particular, to such testers that generate an audible signal representative of the unknown voltage or resistance.
2. Description of the Prior Art
A listing of all the prior art known to the Applicant is set forth in a Prior Art Statement. In brief, although the prior art discloses devices which can generated audible signals in response to an external resistance or voltage, it has generally been necessary that the device be switched from measuring resistances to measuring voltages and vice versa. In addition, none of the prior art discloses or suggests generating an audible sound in response to an unknown alternating current voltage which is indicative not only of its frequency but also of its amplitude. Furthermore, none of the prior art known to the Applicant discloses or suggests an audible voltage-resistance tester which utilizes an inexpensive integrated circuit timer, interconnected to the remaining circuit components of the tester to operate as a multi-vibrator for providing the output signal to a speaker.
USPTO Backgrounds
USPTO Backgrounds