This circuit was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The circuit is based on delayed triggering of SCRs that control a DC load.
In this circuit, which uses one of the four comparators of an LM339 (or LM139 or 239), capacitor C1 and...
This timer activates a relay after a time interval of up to 15 minutes has elapsed, starting from...
This inverter can reach a power of 300 W depending on the transformer used. In this case, a...