Triac output and isolation for AC load switching
The onsemi MOC3051M is a single-channel optoisolator with a Triac output, designed to drive AC loads such as solenoids, motors, or TRIACs in solid-state relay circuits. The 4170 Vrms isolation rating provides galvanic separation between the low-voltage control side and the high-voltage AC line, meeting UL recognized component requirements.
1 kV/µs dV/dt and non-zero-crossing trigger
With a minimum static dV/dt of 1 kV/µs, the output Triac resists false turn-on from fast-rising mains transients — critical when switching inductive loads like contactors or motor starters where line noise is common. The absence of a zero-crossing circuit (Zero Crossing Circuit = No) means the output fires immediately when the LED current exceeds the 15 mA max trigger threshold, enabling phase-angle control for dimmers or soft-start circuits. Off-state voltage is rated 600 V, suitable for 240 VAC line switching with margin for surges. The typical hold current of 220 µA keeps the Triac latched once triggered, preventing dropout on lightly loaded circuits.