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Zener diode connections

  1. Jan 22, 2015 #1
    1. The problem statement, all variables and given/known data:

    I don't know how to do connections.I just know how to do it in specific type of zener diode because i have learn this.I don't understand these connections.Within 30 minutes i have to leave for my exams please help.


    2. Relevant equations
    zener-diode-characteristic-apparatus-500x500.jpg



    3. The attempt at a solution-

    I really don't have any idea.I think it should be like this
    upload_2015-1-23_9-32-10.png
    Please give me general idea how to do connections so that i can do in any kind of zener diode.Please it's urgent.
     
    Last edited by a moderator: Jan 22, 2015
  2. jcsd
  3. Jan 22, 2015 #2

    berkeman

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    Well, I'd love to help, but the pics of the instrument don't help much.

    Basically you will want to plot the I versus V characteristic, for both positive and negative bias of the diode. Use Google Images to see what that IV curve looks like to help you with your lab prep.
     
  4. Jan 23, 2015 #3

    NascentOxygen

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    You have the wrong polarity connection for measuring the zener effect. You also seem to have the wrong connection for the voltmeter. The voltmeter should be connected parallel to the diode, but you show both meters in series with the diode. There needs to be a double-adapter available so that you can plug two wires into the one socket to get this right.
     
  5. Jan 24, 2015 #4
    Can you further elaborate this?
     
  6. Jan 24, 2015 #5

    NascentOxygen

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    The easiest way to get this right would be to connect up the voltage source, the zener diode, and the ammeter. Then, without changing or unplugging any of these wires, add 2 new wires to connect the voltmeter directly across the diode.

    Gingerly adjust the voltage source until the zener current is a few mA. (I say gingerly because there seems no resistance is present to limit the current, so beware that current may increase suddenly with ony a tiny change in voltage source level.)
     
  7. Jan 24, 2015 #6
    How?In series?
     
  8. Jan 24, 2015 #7
    But it is really helpful to me.Can you please correct my connections in the diagram? .
     
  9. Jan 24, 2015 #8

    NascentOxygen

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    Yes, these all in series, except not the voltmeter. A voltmeter always connects in parallel to the voltage it is to measure.
     
  10. Jan 25, 2015 #9
    Means battery ,right?
     
  11. Jan 25, 2015 #10

    NascentOxygen

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    Yes, that's close enough. Though on your apparatus it is called "voltage control".

    The designer has introduced some ambiguity (presumably with the best of intentions) by including a switch labelled forward & reverse, but failing to indicate whether the switch function applies to the voltage control, or maybe the voltmeter. Groan. :(

    You can't be sure until you try it.
     
  12. Jan 26, 2015 #11

    Bystander

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    Does the lab include any sort of instructions with the "box?"
     
  13. Jan 26, 2015 #12
    Which box?
     
  14. Jan 26, 2015 #13

    Bystander

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    The box with the meters, and power supply.
     
  15. Jan 26, 2015 #14

    NascentOxygen

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    It might be a virtual apparatus.
     
  16. Jan 26, 2015 #15

    Bystander

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    That switch --- range for voltmeter? Range for PS output? Commutator for zener socket?
     
  17. Feb 11, 2015 #16
    Observe this video from time 2:19 to 2:44

    In forward bias why positive of battery is not connected with positive of diode?
     
  18. Feb 11, 2015 #17

    Bystander

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    This demonstration is for normal diodes. Current flow through normal diodes is in the same direction as the arrow in the schematic symbol. Zeners will work the same way. When reverse biased, zeners will "break down" without burning up at whatever the rated voltage is for the given zener (provided current is limited to whatever the zener is rated to handle). A "normal" diode when reverse biased at a voltage that exceeds its rating will also break down, but the breakdown is "fatal" for the diode (the "magic smoke" escapes) and it doesn't work at all as a diode after burning up.
     
  19. Feb 11, 2015 #18
    I am concern with normal diodes.
     
    Last edited: Feb 11, 2015
  20. Feb 11, 2015 #19
    Where are battery terminals in the apparatus taken in this video.
     
  21. Feb 11, 2015 #20

    Bystander

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    The red and black terminals (pos. and neg.) in the lower left hand corner ---- it's an adjustable power supply, but same thing for this purpose.
    For normal diodes to have a flow of current in the circuit, you will have to connect them in series ( + to - and - to +) rather than parallel since they do have a polarity.
     
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