inductor in filtering

[bent]

Hello, i've just past the day reading on inductor, and i use the Falstad applet (very cool by the way), for using a inductor into a filtering power supply...

To see if i understand well,
if i took the power supply for the alembic f2-b found on moosapotamus:
http://www.moosapotamus.net/ideas/F2B/alembic.htm
the inductor goes between the bridge diode (pin1) and the first 47uf cap(c5)...
so far so good...
then i use the applet http://www.falstad.com/afilter/ to get the value of the inductor...
at 1H i got a frequency of +/- 23Hz (output), and go down after 5 secondes...
at 5H i got a f= +/-10Hz and goes down after 5 secondes....
at 7,7H i got sometime a f= +/- 7 Hz and flash sometimes but not after 5 secondes...

So the target frequency is to get 0Hz ? so in this type of circuit the best would be 7,7H ?     

Or did i confuse every thing   

Bent

[sean k]

You might want to put the inductor where the 1.5k resistor is so that instead of an inductor input, which will knock the voltage right down to .7 of the rms AC output from the diodes, you have the first cap holding the voltage up then use the inductor to further smooth the ripple... theres a calculation out there somewhere for cap choke cap circuits... but I don't know what it is.

[bent]

you mean a CLCRC filter ?

i'll search for that !

thank's

bent

[gmoon]

Try the free PSU Designer II program from Duncan amps (it's Windoz only, though). Pretty useful for power supply design.

Download here: http://www.duncanamps.com/psud2/index.html.

[bent]

Thank's ,

i try the program, veru useful for design....but i dont understand how reading the result to see how filtering is filtering the HUM...

bent

[defaced]

First we have to understand the problem you're trying to fix. Power supply hum can be caused by ripple voltage after filtering.

[gmoon]

i try the program, veru useful for design....but i dont understand how reading the result to see how filtering is filtering the HUM...

Click on the parameters you'd like to view after you press "simulate"--it will graph each one (voltages and current at each component). The graph will show any ripple...