Found in Popular Electronics from the 90s, this circuit generates signals in a frequency range set to R7 and basically determined by C1. Operational and equivalent transistors can be used.
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...