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You are here: Home / Topics / howto operate a 12 volt dc RELAY with 89C51

howto operate a 12 volt dc RELAY with 89C51

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Electronics › Electronics › howto operate a 12 volt dc RELAY with 89C51

  • This topic has 6 replies, 6 voices, and was last updated 13 years, 1 month ago by AJISH ALFRED.
Viewing 7 posts - 1 through 7 (of 7 total)
  • Author
    Posts
  • December 26, 2011 at 7:14 pm #1472
    ZOBI
    Participant

    i want to operate 12 volt relay with 89C51 any idea?
    i wrote a program which set HIGH at pin 1.0 , although its working and giving 5 volt but does not turn on 6 volt relay
    any idea what to do with this, i have also tried to connect a 2N2222 and also d313 with this pin 1.0 and take output from transistor’s emitter pin making collector common but still it dose not  work ,any additional circuitry i should made?

    December 27, 2011 at 8:19 am #6945
    manohar
    Participant

    emiter o/p of the transister connect to ic ULN2003 n o/p of uln2003 connect to relay.

    December 27, 2011 at 9:56 am #6950
    Qaisar
    Participant

    use any circuit from these 2

    wysiwyg_imageupload:3434:

     

     

    December 28, 2011 at 12:14 am #6953
    ZOBI
    Participant

    Cn i use 2n2222 instead of Bc547?

    Does above CIRUIT 1 work with 2N2222?

    December 28, 2011 at 3:54 am #6954
    Dexter
    Participant

    uln 2003 is the best choice

    for relay driving circuit

    March 4, 2012 at 9:16 am #7229
    Mehtab Ali
    Participant

    use opamp as a comparator for driving the relay

    April 18, 2012 at 2:25 pm #7487
    AJISH ALFRED
    Participant

    I never recommend you to use ULN2004, just to drive a single relay. It has 8 output pins and you are going to use only one. It will just increase the cost and make your circuit complex and bulky.

    Try using a transistor as a switch method,

    Take any general purpose NPN transistor, ground the emitter, collector to one end of relay coil, connect the other end of the relay coil to VCC. Connect the output pin of the controller to the base of the transistor via a resitor of value 10k or less.

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