What will Changing the Capacitance/tor in a ac-dc Transformer Do?

[Techster]

I've been taking apart some basic "wall wart" tramsformers that I've salvaged from junk over the years to use for tinkering, and now I'm wanting to see if there's any way I can 'improve' them in any way

I see that they all have a capacitor rated for around 1000 microfarads & 25v. I have some 2200uF 25v caps and so I was wondering what would happen if I swapped one of those in for the 1000uF one...? Can anyone just tell me the basic effect that increasing or decreasing the capacitance on a circuit like this would have?

It's been a while since I took that ElecEngr class so my memory has gotten fuzzy & I barely recognize any of the stuff in my EE textbook anymore

thanks in advance for any help!

 

[Hero999]

In general to get a 1V ripple you need 10,000:mu:F per amp, so for 1V of ripple on a 500mA transformer use a 6,800:muF capacitor. Remember the component tollerences mean you really need to select a value that's 20% bigger than the ccalculation states.

 

[Sceadwian]

Basically the bigger capacitor is going to give you a higher pulse current ability and a lower ripple at higher loads.

 

[JTECH]

capacitor size

Basically the bigger capacitor is going to give you a higher pulse current ability and a lower ripple at higher loads.

Just don't over do it. Depending on the diode ratings, they may be damaged if the electrolytic cap has too high a value due to the initial charging current required.