Zener Diode/LED error detecting system

Discussion in 'General Electronics Chat' started by Decibel, Jun 11, 2008.

  1. Decibel

    Thread Starter New Member

    Jun 11, 2008
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    I am developing a system to test a power supply with outputs of +5, +12, -12, and +24 voltage outputs. If the assembly of the power supply is correct (as in the voltages are correct at certain test points I have chosen), the LEDs will light. On the other hand, if the incorrect voltage is supplied, my tester should not light the LED.

    Would Zener diodes be the best bet if I hook up the LED in series with a Zener diode and a resistor? For example, if the voltage I'm testing is supposed to be +12 V, and instead it's less than that, the LED shouldn't light due to the Zener. Also, is there any way to indicate if the voltage is greater than +12 V using the same system? (besides the intensity of the LED)

    Thanks in advance.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    I would think that using a meter would be faster and resolve the exact voltage at any point a lot faster. Think about how your tester might show a positive 3 volts at a negative 12 volt terminal.

    Autoranging DVM's are the way to go.
     
  3. oister

    New Member

    May 11, 2008
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    0
    beenthere:

    "I would think that using a meter would be faster and resolve the exact voltage at any point a lot faster. Think about how your tester might show a positive 3 volts at a negative 12 volt terminal."


    dont u think zenor breakdown will occur more by don this???
     
  4. Wendy

    Moderator

    Mar 24, 2008
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