unstable relay

Discussion in 'The Projects Forum' started by jblueink, Oct 17, 2008.

  1. jblueink

    Thread Starter Member

    May 27, 2008
    24
    0
    hi there,
    i design a circuit that uses relay,after i have finished building and soldering every thing was working properly to design specification but if i should use the relay to control an appliance using using an AC supply the relay becomes unstable that is clicking at avery fast rate making the output unstable or fluatuating. please can some one help with a solution...
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    We need a schematic to see what might be wrong.
     
  3. karthik_dm

    Member

    Oct 16, 2008
    27
    0
    --------------------------
    well..normally such problems occur when the supply voltage to the relay coil is not enough..for example if u use a 12DC relay and u are giving 9v means the problem occur ...or else there should be a problem with the driver circuit whis is normally a transistor.."don't forget to use a diode" across the relay coil to prevent back EMF from damaging your driver transistor....an another way of switching AC loads is using TRIACs ....please refer to these relay driver schematics
     
  4. jblueink

    Thread Starter Member

    May 27, 2008
    24
    0
    the relay works properly but once is made to control AC THE PROBLEM START.
     
  5. raybo

    Member

    Oct 18, 2008
    22
    0
    make sure your relay is rated for 120v ac and for the right current. you should use one set of contact to f/b some histerisis to latch it up.
     
  6. jblueink

    Thread Starter Member

    May 27, 2008
    24
    0
    i don't undestand pls can you explain more.in my location we use 230V and the relay is rated for 230V and 200 ohm.
     
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