This circuit was found in a 1967 US documentation. The FET is general purpose and the 6V zener. The circuit has a very fast switching action.
This circuit is from a 1969 Electronics World. The transistors may be modern general-purpose...
This circuit produces signals that depend on the input control voltage. It is a Voltage Controlled...
This circuit was found in a 1967 RCA manual. The transistors are of the time. The adjustment is made to...