This signal injector and tracer (follower) was found in an old American documentation. The transistors can be general use and power is made with one or two common cells.
We find this circuit in a radio amateur publication of 1977. Its purpose is to measure the...
This circuit, found in a 1989 publication, only works with incandescent lamps. The maximum power...
We found this circuit in a 1960 Sylvania transistor manual. The relay can be 12 V and C1...