I am putting together a control circuit for a DC motor. This motor requires 110 volts DC. It must be variable speed. I happen to have a nice continuously variable transformer box that goes smoothly from 0 to 130 volts. This should take care of the speed variations. I hooked this up to a rectifier and the DC that comes out seems to operate the motor pretty well. In reading, however, I discovered that by adding a capacitor across the DC output lines I should be able to smooth the ripples in the DC quite a bit more. There is a schematic of this simple circuit at this site: PowerVolt AN01 Address:http://www.powervolt.com/techan01.html [Broken] Scroll down a little bit to the diagram labeled "Full-Wave Bridge" which is to the right of another diagram. The only clue I have to the value of this capacitor is that it should be "large". The motor, as I mentioned, will be running on voltage from 0 to 110, depending on the particular speed I need. The watts, therefore will also vary, but it is a pretty torquey motor for its size so I expect peak watts will be up there. Can anyone give me an idea what value of capacitor I should try in this circuit? Thanks, Zooby P.S. The motor is 3/4 horsepower.