Low loss metallized polycarbonate lacquer film capacitors can offer new dimensions in the field of high quality miniaturized components. The size of these capacitors is comparable with that of metallized cellulose acetate lacquer film capacitors (1,2) now in pilot plant production at Western Electric Company (6,7,8). However, their properties are greatly superior approaching the low loss characteristics of present polystyrene or of mica capacitors but with a hundred-fold reduction in size. They show a temperature coefficient of capacitance of about SO parts per million per °C, comparable with that of either mica or polystyrene (3,4,5). The polycarbonate lacquer film capacitors also have good capacitance stability, high insulation resistance, and long life under adverse conditions. They may be used without voltage derating over a much wider temperature range than polystyrene, the range extending at least from − 78°C to + 125°C.