Re: LM78XX imput/output capacitors



John Fields wrote:

Eeyore wrote:
John Fields wrote:
Eeyore wrote:
John Fields wrote:
Eeyore wrote:
"vincent.thiernesse" wrote:

these are minimum values.

the input capacitor doesn't replace the filter capacitor.

for the filter capacitor, take 1000uF per Ampere for 1 volt input variation.

I take it you mean ripple ? Your numbers are out by about 7-8:1

You need ~ 8000uF for 1V (pk-pk) of ripple @ 1A load and 50Hz.

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8000µF?

If you want to be pedantic, ***, you might at least try to get
it right.

Let's see your calculation then if you think my number is wrong.

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Idt 1A * 0.01s
C = ----- = ------------ = 1E-2F = 10000µF
dV 1V

Where the hell do you get 10ms from ? I suggest you go and look at a ripple waveform.

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LOL, you really _are_ stupid!

What's the period of full-wave rectified 50Hz?

That's not the relevant answer.

What's relevant is the discharge period. Hint - NOT 10ms. I suggest you either measure or
simulate.

You're not as smart as you claim to be.

Graham

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