# Diode-confused

Discussion in 'Homework Help' started by Key, Sep 24, 2013.

1. ### Key Thread Starter New Member

Jun 21, 2013
14
2
Hello all,
taking a "practical approach" course in my uni for my optional credit points, not part of the official curriculum, but hey, its practical.

Im already stuck with my first assignment, diodes, namely there are a couple of formulas that I have never seen, maybe perhaps you can help me with it.

There is an attachment, the AC voltage is a sinewave.

Can any of these formulas be derived from somewhere and somehow ? I am flabergasted atm.

Regarding the breakdown voltage, can such a thing rly be calculated with such a simple formula ? Aside from being manufacturer specific in the real world, I would assume it has alot more to do with the area of the n and p and far more variables ?

Now a question did arise here. Let us assume we have a no forward voltage drop or break down voltage diode, are the RMS and mean values equal to the formulas I provided, since one side of the polarity is removed...

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2. ### #12 Expert

Nov 30, 2010
16,671
7,314
You are not being asked to calculate the breakdown voltage of the diode. You are being asked the minimum breakdown voltage the diode must have. It's all about the fact that AC voltage is usually stated in RMS values and the peak voltage of a sine wave is 1.41. times the RMS value.

3. ### Key Thread Starter New Member

Jun 21, 2013
14
2
The minimum breakdown the diode must have ? Isnt maximum always better when it comes to diodes ? Except for some cases where circuit protection is needed via zeners ?

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4. ### #12 Expert

Nov 30, 2010
16,671
7,314
Maximum protection is good, but you can't by a diode rated for a million billion volts. You have to buy one that is simply better than the voltage that will be applied to it.