How to use optocoupler

Discussion in 'General Electronics Chat' started by SSR, Apr 25, 2014.

  1. SSR

    Thread Starter New Member

    Aug 6, 2011
    10
    0
    Hi all,

    I need to use an optocoupler as a switch in my project instead of a relay, just for experiment if it work. The information on internet is too confusing. Just to mention i have used a relay and a transistor both separately as a switch.

    Ok so and 6 pin optocoupler (e.g 4n35) has 3 input pins. We use 2 of them to power up the led and leave the third unconnected When the LED lights up it is detected by the photo transistor. The output also has 3 pins, we use collector and emitter and leave the base unconnected. When the photo transistor detects an IR light, does it shorts the collector and emitter so that what ever is on emitter is available on collector or vice versa?

    Thanks.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,571
    2,382
    Essentially yes, you have the option of leaving the base open, and the transistor output turns on from the LED, and you can use either side as the output.
    Usually depends on whether you need to sink or source the data.
    Max.
     
  3. SSR

    Thread Starter New Member

    Aug 6, 2011
    10
    0
    Thanks. Now it will be easy to operate.
     
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