Using the 555 and 7400 this circuit was found in the September 1977 Radio Electronics magazine. The power supply must be made with a voltage of 5 V.
This circuit was found in a 1964 MOSFET applications manual. The circuit uses period general...
This circuit is from a Japanese documentation from 1971, using transistors of the time. The...
This circuit uses Only passive components and have to be plugged to the input of an audio...