All true but I'd pass it all up to use that "rectal plucked" line.
almost ended up wearing my coffee, imagine:
Boss: how did you come up with that value?
The soon to be unemployed me: ------ ;)


At 12:59 PM 10/7/04, you wrote:
>Carlos,
>
>The value is not really unreasonable with a 60Hz supply.  It's hard to=20
>tell the magnitude of the ripple on the bridge output caps C1 and C2 sin=
ce=20
>we don't know what the load current is.  We do know however, that it wil=
l=20
>be at 120Hz and that the designer thought that it would be large enough =
to=20
>bother with additional filtering.  We can calculate the inductive=20
>reactance of the inductors L1 and L2 (at 120Hz) and the capacitive=20
>reactance of the output caps C3 and C4 (again at 120Hz) and see that the=
=20
>designer was trying to reduce the 120Hz ripple.  With inductors and=20
>capacitors an order of magnitude smaller, say 0.1H and 10uF, there would=
=20
>be very little reduction in 120Hz ripple but at the values chosen, the=20
>reduction would be substantial.
>
>There are many combinations that the designer could have chosen and a=20
>variety of tradeoffs that he might have made.  These might include size,=
=20
>cost, availability, reliability and energy storage.
>
>Regards,
>
>Dave
>
>Carlos A. Marcano V. wrote:
>
>>Hi piclisters.
>>
>>I am currently troubleshooting failures on a pretty old power supply. I=
 am
>>attaching the schematic (I hope it is not too big). It is a simple (an
>>inefficient) circuit but there is something that intrigates me, the val=
ue
>>of L1 an L2 which are 1H, (isn=B4t that too much?). If this is right, w=
hy is
>>this value used? Thanks for your help.
>>


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