This optical coupler for short distances is powered by 12 V which is the voltage of the lamp and the relay. The circuit can also use emitting LEDs and the phototransistor can be of any type.
This simple circuit indicates when the two channels of stereo equipment are balanced. The diodes can...
We found this circuit with an operational transconductance amplifier in the Motorola Linear...
This circuit was obtained in an English magazine from 1978. We can easily assemble it because all...