This alarm oscillator was found in the December 1974 issue of Radio Electronics magazine. The power transistor must be equipped with a good heat sink. The Frequency basically is given by C1.
This circuit was found in a Radio Electronics from October 1952. The circuit equalizes the sounds...
This low frequency square wave oscillator using the 741 Operational Amplifier produces sound when...
We found this circuit in an old documentation. The instrument can be an ordinary multimeter in the...