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How do connect a NTE7172 8-Lead DIP with an SCR for a crowbar circuit?

Discussion in 'Radio Circuits, Repair & Performance' started by W6LE, Oct 2, 2011.

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  1. W6LE

    W6LE Ham Member

    I want to make a crowbar circuit to help reduce overvoltage problems on my TS-940. I came across the NTE component "7172 8-Lead DIP", but I can't find clerification on what pins to connect to what part of the circuit. Now I know this is bound to bring some criticism, but I want to use the NTE circuit as opposed to what has been common place. I can't get NTE to cough up any sample diagrams.

    My guess is the Vcc, pin 1, will go to the 28.5 vegulator 'out' and the Vee to ground (this is a positive voltage supply). I believe the Drive Output , pin 8, should be connected to the trip leg of the SCR and the Sense 1 leg, pin 2, to pin 1 of the IC (short pin 2 to pin 1) with the idea that if the regulator out changes more than 2.6 volts, pin 8 will send the drive signal to the SCR and pop the in-line fuse. I thiink there is an internal zenier creating a reference voltage for which the Sense inputs use, or maybe that was a bad dream.
    Anyone willing to put their expertise on the line?
    W6LE
     
  2. WN6U

    WN6U Ham Member

    Try this link.

    http://www.onsemi.com/pub_link/Collateral/MC3423-D.PDF
     
  3. W6LE

    W6LE Ham Member

    David ... Thank you for the reference. Fits just right. :cool:

    Sincerely,
    Jim W.
     
  4. WN6U

    WN6U Ham Member

    You are welcome.
     
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