optocoupler switch

Discussion in 'General Electronics Chat' started by bioukanon, Jun 6, 2009.

  1. bioukanon

    Thread Starter New Member

    Jun 6, 2009
    Hello to all. I need a circuit with a optocouple to switch a relay. The input that I need is 12V and the relay is 12V too. I 'll like to use like a simple relay. Do you pls tell me what resistance must choose and what optocoupler is good to make this circuit. Thanks
  2. DC_Kid

    AAC Fanatic!

    Feb 25, 2008
    here's one (of a milion)

    the resistor needed for opto would be 1050-to-1100ohms.

    you can get 320mA max out of this opto. your relay coil will determine if this is sufficient or not. its also avalanche rated but i would add a diode across the coil to kill the flyback voltage.