Opto Triac vs Opto Isolator: Key Differences Explained

This page compares Opto Triac and Opto Isolator and mentions the difference between Opto Triac and Opto Isolator.

Figure 1 depicts the Opto Triac circuit symbol. It is a 4-layer, 3-terminal device. It blocks current in the OFF state. When triggered by a gate pulse, it conducts current in both directions. The triac that operates based on a light signal is known as an opto triac. As shown, an LED is used to provide light for the triac to conduct.

The LED emits light when powered ON.

Figure 2 depicts an opto-isolator, which uses an LED and a phototransistor. The device prevents and blocks light reflections back to the device where it’s used. This prevents damage due to high optical power. Isolation and insertion loss are the two main parameters to consider when selecting an opto-isolator for use.