Larry wrote
> ....The transformer secondary voltage will be 0.707 times the output DC
> voltage (roughly depending on many component characteristics) so
> therefore the transformer secondary current rating will need to be 1.414
> times the output DC current. Nobody ever gets this right!
>
> The peak current through each diode leg will be *EIGHT* times the output
> DC current! Pay attention to the peak repetitive current rating of the
> diodes. They derate very fast with temperature and this IS a critical
> parameter.
It's worth pointing out that the peak current in the transformer
is the same as the peak current in the diodes. The heating effect
of the current flowing in short peaks (in a cap input supply) is
2.5-3x what you expect working back from the average dc current in
the load.
A transformer where the secondary is rated for either choke input
or resistive load will disappoint (and fry) when used at that
average current with capacitor input.
Steve
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