This circuit with two operating modes was found in the September 1989 issue of Radio Electronics magazine. Other operational amplifiers can be used. The power supply must be dual.
Found in American documentation this circuit uses transistors of the time. The circuit can be made...
The TAA300 integrated circuit is not common today. In fact, the circuit shown is from a Dutch...
This circuit was found in a 1980s documentation. Q1 and Q2 can be BC548 and SCR a TIC106. The...