Resistor configration for safe use of a triac

Discussion in 'General Electronics Chat' started by clintonb, Jun 1, 2016.

  1. clintonb

    Thread Starter Active Member

    Mar 6, 2011
    I was looking in the datasheet of an optocoupler that will trigger a triac and they provide a very basic layout and resistor values for the gate resistors and a capacitor across the optocoupler.

    I came across another circuit that came out of an existing machine and they had put a very small resistor of 100 ohms from the gate to the MT2 termal which connects to the neutral which rings similar to a 10 ohm resistor connected as a pull down resistor on a mosfet to make sure it turns off.

    Is this infact what this is and what would be the correct size of this resistor?
  2. MaxHeadRoom


    Jul 18, 2013
    Check out Fairchild App note AN-3006.