This circuit was found in a 1989 publication. The operational amplifier supports equivalents. The LED range can be expanded.
This optical switch was found in an old Texas Instruments opto-electronics manual. The relay is...
This op amp circuit is based on a 555 IC and two common op amps. Transistors are general purpose....
This Testa o Croce (name in Italian) was obtained from an Italian magazine in 1994. The circuit can...