Zener diode as voltage regulator

Discussion in 'General Electronics Chat' started by Manoj Sahu, Oct 5, 2014.

1. Manoj Sahu Thread Starter New Member

Sep 29, 2014
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How Zener Diode is used as voltage regulator? Please explain with circuit diagram and in detail

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2. djsfantasi AAC Fanatic!

Apr 11, 2010
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Is this an assignment? Homework?

Apr 5, 2008
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4. Manoj Sahu Thread Starter New Member

Sep 29, 2014
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No this is not an assignment.

Apr 11, 2010
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6. Manoj Sahu Thread Starter New Member

Sep 29, 2014
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I've read the Article from Electronics-Tutorials. But a sentence from there is confusing me. First there written the voltage across R is always
the same as the zener voltage, ( Vz = Vr ). And at last The supply voltage Vs must be greater than Vz . So this means Vs is always greater than Vs due to initial voltage drop in Resistance. So is my speculation is correct that Vs is always greater than Vs due to initial voltage drop in Resistance.

Last edited: Oct 5, 2014

Aug 23, 2012
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8. Papabravo Expert

Feb 24, 2006
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V sub R is not the voltage across the resistor it is the Reverse Bias voltage ACROSS THE ZENER DIODE. V sub z has a fixed value for each diode. It will vary a little bit from diode to diode in a lot of "identical" diodes. V sub R in a given circuit will vary from zero to some negative value where the junction breakdown occurs. The purpose of the resistor in a zener diode regulator is to limit the current through the zener diode so that breakdown will NOT occur.

You are correct that V sub S will always be greater than V sub Z. This is true of all linear regulators. It is only untrue for some types of switching regulators.

Does that clear things up a bit?

9. Manoj Sahu Thread Starter New Member

Sep 29, 2014
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Yes it's clear now. Does temperature affect the working of Zener diode ? As lot of diodes are temperature dependance.

10. Sensacell Senior Member

Jun 19, 2012
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Zeners make pretty crappy regulators in general, not used much except where poor regulation and power waste can be traded for circuit simplicity.