ELECTRICAL NOISE CHARACTERISTICS OF CARBON-BLACK-FILLED CHLOROPRENE RUBBER

The DC electrical resistances of certain chloroprene rubbers with carbon black filling exhibit positive temperature coefficients (PTC effect) for certain concentrations of the conductive filler. The electrical noise exhibited by these rubbers has been studied. The thermal noise is shown to obey Nyquist's theorem to a good approximation. The current noise shows a 1/f frequency dependence, and the noise power is proportional to the square of the applied bias voltage. This applies to samples exhibiting a wide range of resistivities, from over 107 Ω cm (20% carbon black) to under 100 Ω cm (35% carbon black by weight).