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@keeping trying • 08 Apr, 2009

hello ,

I have assignment and there is the following question in it
Actually I answered some of them but I am not sure
I Drew the circuit and I tried to put here but I couldn't ,
However, these are the questions

1-what should be the PIV rating of diodes in the circuit ?

my answer :
We used bridge rectifier diode in the circuit which has PIV which should be more than 130 v in this " the maximum voltage" which should be safely applied , otherwise the diode will breakdown , also it should be at least 50 volts at room temperature because it effective by room temperature , it increase with it and decrease with it too. Another Point It is important to remember that this is a peak value of voltage not the root-mean-square (RMS) value. As a
“Rule -of-Thumb, to provide a margin of safety, the PIV rating of a diode should be at least 3 times the RMS .
note : 130 the input voltage

2- if one of the diode in the rectifier is opens , what should be the possible output voltage ?

3- if one of the diode in the bridge rectifier shorts what are the possible consequences ?

4- discuss the effect of change in the value of filter capacitor used ?

5- what happens to output voltage of a rectifier if the capacitor becomes very leaky ?

6- if the primary winding of the transformer in the power supply , what will you observe in the rectified output ?
Any change in the primary current will cause a change in the flux, which then induces avoltage in both the primary and secondary coils.

7- the dc output voltage of the filtered rectifier is less thae it should be . what could be the problem ?

the voltage diodes dropped because of the deplition region ​
please can you check my answer and help me to find the rest answer ?!!​
thanks alot ​
@Rifaa • 08 Apr, 2009 PIV is the peak inverse ( reverse ) voltage you can apply to a diode or PN junction before it breaks down.
Which basically means the diode will short circuit if the PIV is reached.
A diode has two voltage rating
1 is forward voltage. 0.6V for a typical silicon diode.
2 is the reverse voltage which it will block the flow of current for any given voltage.
Zener diodes is an exception

for ex: take 1N4001 Which is a 1 A general purpose diode and it has a PIV rating of RMS 50 volts. So to say if u apply any voltage beyond PIV forward or reverse, you'll get faulty diode. may open or short circuit, might get leaky too 😉
I can answer the rest if u post back.
It's really sad to see tht CE's don't visit regularly or answer newbies. I think they are too busy.
I am too, but I'll help if time permits


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