how zener functions in the circuit?

Discussion in 'Analog & Mixed-Signal Design' started by zippora, Aug 28, 2016.

  1. zippora

    Thread Starter New Member

    Aug 27, 2016
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    Please find attached the file. Here Zener ZD1 is 10V zener. What can be the purpose of introducing zener there?


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  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,879
    371
    The ZD1/Q1 operates the relay when the supply voltage is high enough, in this case around 12V.
    When the voltage is lower the zener doesn't conduct, Q1 and the relay are off.
     
  3. zippora

    Thread Starter New Member

    Aug 27, 2016
    10
    0
    Thanks.
     
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