Optocoupler Circuit Diagrams

Optocoupler Circuit Diagrams When a computer must control an external device -specially when the device is powered by AC voltage - the computer must be electrically isolated from the external device to prevent possible damage to the computer, when something goes wrong with the external device. The simplest way to do this is to use a transformer. However, by relaying short control pulses or high freguency signals, an optocoupler works best. The circuit featured here uses a comparator following the phototransistor. The comparator has a TTL compatible output. Potentiometer P1 varies the threshold level of the comparator.
optocoupler-circuit-diagrams
Optocoupler Circuit Diagrams

Optocoupler Circuit Diagrams

When a computer must control an external device -specially when the device is powered by AC voltage - the computer must be electrically isolated from the external device to prevent possible damage to the computer, when something goes wrong with the external device.

The simplest way to do this is to use a transformer. However, by relaying short control pulses or high freguency signals, an optocoupler works best.

The circuit featured here uses a comparator following the phototransistor. The comparator has a TTL compatible output. Potentiometer P1 varies the threshold level of the comparator.