Solid State Schematic

Discussion in 'The Projects Forum' started by westhomas, Oct 1, 2008.

  1. westhomas

    Thread Starter New Member

    Sep 29, 2008
    6
    0
    Hi,

    I'm attempting to switch on a load using this SSR - S202S12 and the datasheet has included this 'standard' circuit.

    Can someone explain what the Z symbol represents? Is that a zener diode, and if so is there a specific rating required based on the load being driven? (I'm driving an inductive load)

    Thanks in advance for any help....
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The symbol is for a transient surge absorber. It will go from an extremely high resistance to a very low one if the rated voltage is exceeded. The idea is to pop the protection device and keep the voltage spike from damaging the load.
     
  3. westhomas

    Thread Starter New Member

    Sep 29, 2008
    6
    0
    thanks!

    would then a fuse perform the same function?

    or could I harvest this component from a surge protector?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    A fuse would simply blow, as it would connect the two line (briefly). For proper operation, the trip voltage should be a bit above the line it is protecting. You could go to Panasonic's web site and look over their line of ZNR transient surge absorbers and get a better idea of their function. Most cost under $.50.
     
  5. westhomas

    Thread Starter New Member

    Sep 29, 2008
    6
    0
    right, of coarse a fuse would blow if you put it across a line.

    Also referred to as 'Varistors' - I see the meaning of this now on the datasheet for the relay.

    thanks for your clarifications.
     
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