NPN and PNP transistor tester (CB22146E)

This simple transistor tester was found in old English documentation. Suitable for general purpose transistors.

Transistor Audio Oscillator (CB12375E)
This circuit is from a 1974 publication, but it can still be easily assembled today with BC548...
Driver TAA435 (CB7254E)
This driver for audio signals using the TAA435 integrated circuit was found in Philips 1968...
Automatic Gain Control for Recording (CB24224E)
We found this circuit for old tape recorders in the December 1972 Radio Electronics magazine. The...