Opto Coupler (photo transistor)
A very nice isolator but in very small package!. Yes it is opto Coupler .. you can switch a circuit by micro controller but fully isolated from high voltages or noises. Pin 1 : positive pin of Diode Pin2: negative pin of Diode Note: micro controller will light on this diode and not connected to photo transistor . It send comment by light to transistor Pin3: emitter pin of photo transistor Pin4: collector pin of photo transistor You can connect pin 3 and 4 to any circuit and relay to contact its wires but isolated from microcontroller pin 1 is pin with circle ⭕ mark
