This voltage-controlled oscillator was found in a 1965 Electronic Design. Transistors are from the time, and modern equivalents can be tested.
This circuit was found in a Philips documentation from 1970. The components are of the time,...
This circuit divides the frequency of a 2 kHz signal by 2. The circuit was found in Philips...
This circuit was found in an English publication. The components are current, and the transformer must be...