This simple transistor tester was found in a Japanese magazine in 1967. It tests general purpose transistors of both the NPN and PNP type and is powered by 4 batteries (6 V).
Found in a 1969s American documentation, this circuit uses transistors from that time. The...
We found this circuit in a Radio Electronics magazine from January 1975. The transistors are...
This low-current control circuit has a lamp as a load, but can have other types of devices, such...