This transistor curve tracer was described in a December 1969 Radio Electronics article. It consists of a ladder-type signal generator that applies stepped voltages to the transistor under test.
This circuit is from a 1974 publication, but it can still be easily assembled today with BC548...
This driver for audio signals using the TAA435 integrated circuit was found in Philips 1968...
We found this circuit for old tape recorders in the December 1972 Radio Electronics magazine. The...