This code practice circuit was found in a 1990s issue of Radio Amaterur Today magazine. It produces an audio tone with the 555.
This project was found in a documentation from 1980. It is a central of sound effects, a simple...
This amplifier for public address was found in English documentation from 1967. The transistors are from...
This circuit was found in an English magazine from 1978, but it is still current, just change the...