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.
In the circuit shown in the figure we have the way to excite a small speaker from a TTL output. The...
This fuzz uses only one transistor that can be the BC548. Signal input and output cables must be...
This circuit is from a 1977 documentation. It is powered by the power supply of the circuit under...