Transistor-magnetic control circuits for aircraft electric systems

The stringent requirements for military aircraft electric systems necessitates the optimum utilization of the latest component developments. The circuitry described in this paper is intended to combine semiconductor diodes and transistors with square-loop magnetic cores in a manner that results in the maximum use of their desirable characteristics. The memory capability of square-loop magnetic cores and the switching characteristics of transistors are employed in a complementary manner. As a result, the following advantages are obtained: 1. The transistor-magnetic high-phase and low-phase sensing circuit inherently senses the “true average” value of the system alternating voltages. In other words, it senses the total amount of volt-seconds underneath the positive half cycles of the voltages. This is in contrast to conventional circuits which sense either the peak value or only a small fraction of the volt-seconds underneath the waveform. 2. Because only the switching characteristics of the transistors are utilized, circuit operation is practically independent of variations in transistor characteristics. 3. The circuits use only small, static, reliable, and rugged components. Capacitors, which are used in conventional circuits, are replaced in this circuit by square-loop magnetic cores which are less temperature sensitive and much more reliable.