frogman

Hey folks, thanks for input. It is all making much more sense. I need to get myself an o-scope though. Am also reading the AC circuits pdf on the site which is enlightening if not long and technical. :-) One question that someone might be able to answer is does running a DC motor with voltage ripple damage the motor at all, or just affect its performance? Hamish

Thank you for help with this! I have been having fun lifting weights by blowing up ballons under a bowl with my newly powered mini air compressor. :) One thing though, I didn't understand the forumla, just apprecited the outcome - could someone clarify what p-p stands for? Hamish

Hi there, I'm trying to work out how to calculate the voltage output of a capacitor that I want to use as a filter after using a bridge rectifier. The output from the secondary coil of the transformer is 12vAC max 4amps. The rectifier has a max of 400V and 8amps. I want to understand how to work out what capacitor size I need to get a filtered 12V when I connect it in parellel with the rectifier outputs. I used a 2200uf capacitor and my volt meter said about .3V. I then added a second 2200uf capacitor in parellel and I read 18V! Can anyone point me in the right direction? Cheers, Hamish