# Zener Diode question

Discussion in 'Homework Help' started by Matthew Foo, May 24, 2015.

1. ### Matthew Foo Thread Starter New Member

May 1, 2015
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Hi all I'm having problem solving the question below , anyone can guide me with the answer step by step .
Thank you all

2. ### MikeML AAC Fanatic!

Oct 2, 2009
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It would be useful if we could see how far you can get.
For starters, can you tell us what Vzt, Izt, Izk, Zz, and Izm mean?

Oct 10, 2011
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4. ### Matthew Foo Thread Starter New Member

May 1, 2015
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Vzt = Zener test voltage , Izt = zener test current , Izt = zener knee current , Zz = Zener Resistance & Izm = Zener Maximum current.

Thanks sirs

5. ### MrAl Distinguished Member

Jun 17, 2014
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521
Hi,

The first thing you would have to do is determine the model parameters of the zener.

Given that the test voltage is 4.8v at a test current of 36ma and internal resistance of 10 ohms that means that the zero current voltage is:
Vd0=4.8-0.036*10

So you have that voltage source in series with a 10 ohm resistor to start with, and that replaces the zener diode. This gives you a circuit with two voltage sources and three resistors which is solvable using standard methods.

See what you can do with this information.

6. ### Matthew Foo Thread Starter New Member

May 1, 2015
3
0
any solution for this ?

7. ### MrAl Distinguished Member

Jun 17, 2014
2,566
521
Hello,

Do you know now to analyze a circuit with two sources and three resistors?

The zener gets replaced by a source with a series resistor. Then you solve the circuit.
For the Power question, you'll have to assume that the variable resistor never pulls the zener voltage lower than Vz0.
Vz0=Vd0=4.8-0.036*10=4.44

Can you figure out the rest?

8. ### WBahn Moderator

Mar 31, 2012
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You need to show YOUR attempt to answer YOUR homework problem. That will give us a starting point to see where you are going wrong and how we might best help you get back on track.

9. ### WBahn Moderator

Mar 31, 2012
18,088
4,917
It might help if you sketch the typical Zener characteristic and then the piecewise linear model implied by the given parameters.