Zener Diodes section - error after ohms law section

Discussion in 'Feedback and Suggestions' started by Recrex, Apr 25, 2012.

  1. Recrex

    Recrex Thread Starter New Member

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    Hi,
    New to this forum, but the article says to notify you of any errors we catch. So here I am... :)

    In the Zener Diodes article, mid way through there is a discussion of adding a load to the circuit and calculating the current, etc. More importantly, finding out if the zener is even turned on looking at the R-dropping resistor.
    At the end of the calculations box figuring out (using Ohm's law) what the minimum R-dropping resistor should be is a paragraph described below:
    "Thus, if the load resistance is exactly 38.889 kΩ, there will be 12.6 volts across it, diode or no diode. Any load resistance smaller than 38.889 kΩ will result in a load voltage less than 12.6 volts, diode or no diode. With the diode in place, the load voltage will be regulated to a maximum of 12.6 volts for any load resistance greater than 38.889 kΩ."

    okay, a couple of words are reversed - Any load resistance 'smaller' - should be 'greater'. (as the example of 100K proves). Like wise - the last line ....for any load resistance 'greater' - should be 'smaller' to keep the 12.6 volts.

    Hope this helps.
  2. Bill_Marsden

    Bill_Marsden Moderator Staff Member

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    Dallas, TX (GMT-5 w/ DST)
    Part of the problem is you are taking the paragraph out of context. An earlier set of paragraphs set up the problem as follows.

    After several problem worksheets to demonstrate the principle it follows with your problem paragraph.

    As you can see, we are talking two different cases, two different circuits. The author was discussing what the minimum resistance could be (maximum load).

    A smaller resistance will result in less voltage across the load. This is a true statement. The loading (not resistance, but amps) would be greater.

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