Using MOC3021 opto triac for direct load switch of a power supply

Hi. I'm trying to use an MOC3021 opto triac to switch On/Off a little power supply(the 230 V side). I want to use it for direct load switch, not using it as a driver to a second triac. In MOC's datasheet it is a "warning" such that: "This optoisolator should not be used to drive a load directly. It is intended to be a trigger device only." Should i use it for direct load switch? This MOC can switch 400 V and 1 A. I only have to switch 230V and 100 mA. Any opinion? Thanks.

opto triac

Hi,

The data sheet that I looked at said "peak repetative surge current of 1 amp" with the note of pulse width of 1 millisecond. So the rating is not quite what you think it is. However having said that the main limitation for the device and the application seems to be the devices power disipation limit of 330mw. Figure how much power you will be disipating in the device and if your surge current will exceed the pulse rating. The statement from the manufacturer about not using it directly may be implying that should there be a failure of the device there could be a cross over of voltage as the device blows up internally and allows the line voltage direct access to your low voltage dc side without a current limit of even a resistor. That would be a guess on my part but could happen. Anyway, If I were in your shoes I would use another external device just to be safe. Not expensive, easy to drive and at your current levels a very small device could handle it.


good luck

dfullmer