This circuit was found in 1967 Philips documentation. It uses transistors from that time. Transistors can be replaced with modern equivalents.
Although indicated in the original publication of the 1980s as a capacitance switch, the circuit...
This circuit was obtained from an English magazine from 1980, but as it uses components that can...
This configuration that appears elsewhere on this site was found in a Popular Electronics of the 1980s. The...