Why would you use an optoisolator instead of a transorb?

Discussion in 'General Electronics Chat' started by upopads, Sep 30, 2013.

  1. upopads

    Thread Starter Active Member

    Dec 18, 2007
    Hi I have a question about electronic components. I am a new designer and I have been reading about optoisolators/optocouplers this morning and my understanding is that these components are mainly for designs which contain sensors. But wikipedia also suggests that they can be used for transient, high voltage protection also. I always thought that that was what what the application of the transorb was for. So I would like to know if anyone could help clarify this for me a little?
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    The main idea is the optocoupler provides true electrical isolation, there is no current path from input to output, yet signals can pass through.

    This component allows circuits operating at large voltage differences to be safely interconnected.

    This is relevant to transient protection if you consider that the isolation blocks a potentially damaging current flow - no path, no current = no damage.
  3. upopads

    Thread Starter Active Member

    Dec 18, 2007
    That helped a lot, thanks.
  4. ramancini8


    Jul 18, 2012
    An optocoupler does not protect against lightning because lightning voltages are so high.
  5. crutschow


    Mar 14, 2008
    An opto isolator provides isolation between its input and output. It does not absorb high transient voltages but can prevent them from being transferred from input to output.

    A Transorb acts like a high power zener diode to clip high voltage transients in a circuit. It provides no circuit isolation.