We found this circuit in a 1968 Electronics World. The transistors are from the era and information about the transformer was included. Transistors support current equivalents.
In this circuit, suggested by the Motorola Linear Databook of 1990, the resistors depend on the...
This circuit is used for cable checking. We found it in the Radio Electronics magazine of December...
We found this circuit in a 1965 Electronic Design. Transistors are still common but admit...