10 Nov
2005
10 Nov
'05
5:48 p.m.
From: "Bill Pechter" <pechter at
gmail.com>
I believe that you can get by with a fairly wide range of diodes and
caps if you just readjust the video after throwing the cap and diode in.
If I remember correctly the diode was 50v -- and should be at least 100
as you say.
---snip---
Hi
Just as a rule of thumb, the diode needs to be rated
at least 2 times the output voltage for an AC input.
This is not overrating! It actually needs to stand
off that much reverse voltage.
Some pulsed AC supplies, such as switchers may not
need that high of a voltage because the voltage
is not symmetric, on both polarity swings.
If you want to overrate the diode, go to 3 to 4
times the voltage out. 2 times is not overrating,
that is the normal operation level.
Dwight
12 Nov
12 Nov
12:41 a.m.
Just as a rule of thumb, the diode needs to be rated
at least 2 times the output voltage for an AC input.
Assuming there's a capactor on the output side of the diode (e.g. the
smoothing capacitor of a power supply), that will charge to the peak
voltage of the AC input. On the next half cycle, the cathode of the diode
will be at that voltage above ground, while the anode will be at -ve the
same voltage. Therefore you get twice the AC peak voltage across the diode.
And note that it's the peak and not RMS voltage you have to consider.
-tony
6997
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ard＠p850ug1.demon.co.uk -
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