The MOC3021 comes in an internal light-emitting diode and a TRIAC based light activating based transistor. This optocoupler provides protection from HIGH resistive and inductive loads. It has the ability to flow the current up to 1A. Optocoupler has multiple types and every type has almost the same operating functionality, but sometimes its internal structure makes it different. MOC3021 - Optoisolator Triac Output 5000Vrms 1 Channel 6-DIP from Lite-On Inc. They are designed for interfacing between electronic controls and power triacs to control. The MOC301XM and MOC302XM series are optically isolated triac driver devices. Download MOC3021 Texas Instruments.