This circuit converts a high voltage into a frequency using an optical coupler. The transistor can be 2N2646 and the coupler admits equivalent. The circuit is from a 1974 publication.
Obtaining a voltage that is proportional to a current drained by a load can be important in...
The good signal of this circuit depends on L1 and C1. For 80 turns of wire 28 with a central...
Found in a 1966 General Electric manual, this circuit provides a delay in starting. The motor is...