From the printed documentation of U.S. Pat. No. 5,889,445, components of the above-mentioned type are known in which one external contact each is located at both ends and at two long sides. The professional knows these components also under the name “feed-through components”. The external contacts located at the ends are applied by dipping the foundation in an electrically conductive paste and fit therefore over the ends like a cap. Because of the location of the external contacts and the way they are manufactured, the known component has the disadvantage that its dimensions cannot be reduced to less than 2.0 mm in length and 1.25 mm in width, because the external contacts must have a minimum separation from each other so as to avoid short circuits through surface currents.
Current designs for cell phones require smaller dimensions than the ones mentioned above, which is the reason why the known components cannot be considered for this type of application.
The relatively large dimensions of the known components also have the disadvantage that they result in a large parasitic inductance that has a negative effect on the attenuation properties of the component used in cell phones as a noise suppression component to filter out interfering frequencies.
The known components can be used as varistors by using varistor ceramics in the dielectric layers, but even here the large dimensions of the component are a disadvantage, in particular with regard to parasitic inductances as well as relatively high terminal voltages with steep-sided pulses.
The known component also has the disadvantage that four different sides of the foundation have to be coated when applying the external contacts, resulting in a large expense, for example for the turning of the component.
USPTO Backgrounds
USPTO Backgrounds