The examination of electric contacts by the plastic replica method

ELECTROMECHANICAL switching devices, typified by the relay, are used by millions in the communications industry and have been developed to a high degree of perfection and specialization. Their reliability is such that only a few failures per billion contact operations are expected under telephone operating conditions. The use of twin contacts of noble metals, improved contact actuation, erosion control, and cleaner operating environments all have contributed to this perfection.