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Burglar alarms

  1. Jan 12, 2014 #1
    I don't understand what exactly a transistor does in a burglar alarm. I read somewhere that this is its application as a switch but isn't it the LDR which works like that in this particular circuit? It would be really helpful if someone could explain the working in detail, I can't seem to find any proper explanation on the net.
  2. jcsd
  3. Jan 12, 2014 #2


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    there's probably a few individual transistors and a number of IC's that contain many transistors in any given alarm unit.
    Your question is pretty meaningless till you give us more information to go on
    Do you have a specific alarm unit?
    do you have a circuit diagram for it so we can see what specific transistor(s) you are referring to ?

    Transistors can be used ( amongst others things) as a basic switch

    Last edited: Jan 12, 2014
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