unregulated wallmart power supply cap size

ash_dac

Member
2005-01-27 8:22 pm
UK
Hi,


I opened up an unregulated ac wallwart for my QED Digit dac today. (The wallwart contains a transformer, 4 diodes, and 1000uf noname capacitor).

The wallwart is 12V dc (500mA).


Can I safely replace the 1000uf cap with a 100uf cap ?

(I have some 100uf 25V Black Gate capacitors )




Kind regards,


Ashley.
 
If it is an input cap after the bridge....then this won't do much since the SMPS flyback ciruit will adjust it's duty cycle for input voltage variation...
If the cap you are refering to is a output cap..then you should not deviate from it's original value, you run the risk of putting the SMPS into instability and oscilation... The output cap and Load resistance provide a POLE that is compensated by the error control loop....move the cap, then you may move the POLE and make problems...
Unless this thing is UNREGULATED?? ::rolleyes:

Chris