Transactions section: Preprint of corresponding pages from the current annual AIEE transactions volume

MICA CAPACITORS by the millions have been used in radio, radar, and other important electronic equipment for our Armed Forces. The unprecedented demand has strained all our resources, and much time and money have been spent in efforts to solve the mica supply problem. One of these was a research project conducted by Bell Telephone Laboratories for the War Production Board. It was concerned with the development of electrical test methods to predetermine the quality of raw mica in terms of end-use requirements in various grades of capacitors. After over two years of work covering development, design, laboratory trial and an extensive commercial trial of two types of test instruments, this project has been brought to a successful conclusion. As the electrical method of classification makes possible the use of mica available in large quantities, but previously considered unsuitable for capacitors, the mica supply for capacitors is greatly increased. An estimated saving up to 60 per cent of the total amount of higher-quality mica used in capacitors is indicated.