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BAT48 for Bridge Diode?

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sansan:
I have some BAT48. Can I use it as a casual rectifier?
Datasheet says:
IF is 350mA, IPk is 7.5A.
 
The trafo is 200mA, expected load is about 20mA. But, will the diode damaged by the large reservoir cap?

mariush:
You would want to be careful about peak reverse voltage, they're kind of low at 40v but probably fine with that transformer.

The capacitance doesn't seem that high to me... don't think's gonna be an issue. Consider if you really need that big capacitors though, as you say the load is only 20mA  ... you can sort of approximate capacitance needed with formula  C = current / [ 2 x ac frequency  x ( Vdc peak - Vdc min desired)]

At 20mA, you're probably fine with a couple 470uF capacitors. Guess it depends how much voltage drop you're willing to tolerate.

sansan:
the load will be less than 20mA (2 opamp). I've been using schottky diode near its reverse voltage for years, never had a problem..  ;D

I'm affraid the surge current (first charge upon start-up) of the caps will blow the diode, but the trafo is only 200mA.
I wonder if the caps surge current will be limited by the trafo itself.

I think I understand that a big trafo can take (primary winding?) a lot of surge current upon start-up.
But, is this tiny trafo can give (secondary winding?) way more current during first start-up??

thanks mariush, I'll try using BAT48 anyway. I hope it won't blow up  :-DD  |O

Kleinstein:
With a small transformer the internal resistance of the transformer coils would limit the current spike.
How much resistance really depends on the transformer and small one can limit the current quite a bit. 12 V and 200 mA are only 2.4 VA and thus a rather small one. The better data-sheets give the ratio of unloaded and nominally loaded voltage and one can calculate the resistance from that.

With the low load the voltage of the transformer can be quite a bit higher (e.g. 1.5 x)  than nominal. So one may not need the low drop of shottky diodes and the peak voltage may indeed become an issue. The didoes have to withstand 2 x the peak voltage. One would more tend towards a ready made bridge rectifier.

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