An Experimental Automobile Receiver Employing Transistors

This paper describes an experimental automobile broadcast receiver utilizing nine experimental junction transistors in a superheterodyne circuit. The receiver operates directly from the six-volt storage battery without vibrator, power transformer, or rectifier. The average current drain, including that for two pilot lights, is approximately one-tenth that of a conventional automobile receiver. The performance of this receiver is comparable to that of conventional automobile receivers. Particular emphasis has been placed on maintaining performance over a wide range of ambient temperature, both to accommodate the severe requirements specified for automobile service, and to establish the operability over such a temperature range of apparatus employing germanium transistors. The receiver circuits and performance characteristics, including performance data for the ambient temperature range -40 degrees C. to +80 degrees C., are described in detail. Techniques which render circuit operation insensitive to variation of ambient temperature and which permit interchangeability of transistors are discussed.