optoisolator - triac\SCR - FOR DC !!

Discussion in 'General Electronics Chat' started by yehezkel2, Jan 6, 2010.

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  1. yehezkel2

    Thread Starter Member

    Oct 2, 2009

    i'm using a microcontroller to control these two ports:

    • drive a MOC3020 optocoupler that drives a triac that control an AC device - working well.
    • now i need the microcontroller (outputs ~4v) activate the discharge of a 700v DC capacitor through a resistor.
    i tried using the same setup of optocoupler with a triac for activating the capacitor discharge, but the problem is that the TRIAC will stay ON until the capacitor is fully empty, even if the microcontroller stopped the optocoupler. this is because triac's behavior with DC voltage.

    i need to do it with an optocoupler as well, to insulate the microprocessor from the capacitor's 700 volts.

    can i use a MOC3020 (that has a triac output) and use it to drive an SCR for discharging the capacitor ? or the SCR will behave like a TRIAC because of the optocoupler being a triac output ?

    then i guess i need an SCR-output optocoupler - can you recommend part numbers or how to find these ?

    thanks a lot !
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Sorry we can't help you - that is too much energy to fool with.

    From our rules:
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