Metal Oxide Varistor: Zinc Oxide with 0.2 % Bismuth Oxide, 800 °C, 1.0 mm (Masuyama 1972)

A non-linear resistor: the current through it rises far faster than the voltage across it. Masuyama, Matsuoka and Nishi made one from zinc oxide with a little bismuth oxide: pressed into a disc, sintered, lapped, and given metal electrodes. With 0.2 mole % bismuth oxide, sintered at 800 °C and lapped to 1.0 mm, the disc measured a C-value of 81 at 1 mA and a nonlinearity exponent n of 3.2. Source: T. Masuyama, M. Matsuoka and T. Nishi (Matsushita), US 3,663,458 (1972), Example 1. Unknown: what the silver paint is. The patent calls the spraying and the paint well known. The spraying is ours, after US Army Corps of Engineers EM 1110-2-3401 (1999). The 10 g batch is our arithmetic. Picture: the patent's drawing.