This circuit for incandescent lamps was found in a 70s documentation. The circuit uses an SCR according to the power of the controlled lamps. The delay is a few seconds, given by capacitor C1.
This simple receiver with junction FET uses a high impedance magnetic earphone (over 2 k). Power...
This HeNe laser power supply was found in the March 1989 issue of Radio Electronics magazine. This...
This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz...