Hi all,

Working on my power supply, using the transformer and bridge rectifier from an old audio amp (Im also going to use the case to house the supply and my driver boards etc)

I have identifed the windings and got myself 5V DC regulated using a 7805 regulator with the standard couple of capacitors (from 9V windings on the transformer) and also 36V (from 25 VAC windings).
The 36V goes through a bridge rectifier, with a smoothing capacitor which was temporarily 4700uF 50V, this wokred fine in a test driving a motor. I read up and calculated the capacitor value for my system which came to about 17000uF. The nearest I could source without paying the earth was 2 x 10000uF 100V capacitors (new) from ebay. My idea was to parallel these giving me 20000uF. They arrived, and are MASSIVE ! They measure about 4 1/2 inches high by 2 1/2 inches accross. Have I got the right ones? I wasnt expecting anything this big. The spec of them is:

10000uF -10 +50 %
100VDC
MAx ripple 14.9A at 100Hz @ 85C
55/085/56 (not sure what these numbers mean)

Here is a pic of one. Can anyone please tell me if these are ok to use ?

Thanks

Calv

 

Should be ok to use. Capacitor should be rated at 20 % higher than power supply output voltage.
Capacitance should be  equal or greater than 80000 x I/V  where I is the current and V is the voltage.
RICH

Hi,

I assumed so but was suprised at the size of them. Are they all that big at that rating ? I presume 50V ones will be smaller but I couldnt find any at a decent price.

Thanks

Calv

The ones I used are smaller in diameter but taller.
RICH