im building a high current regulated variable lab supply and looking for some help with filtering. Im using a hand wound microwave oven transformer that puts out 30VAC and TONS of amps. the problem is that the electrical noise and ripple repeatedly burn out the IC and Transistors.(this thing vibrates my whole kitchen table!! ) i attached a schematic. I found interesting info @ http://forum.allaboutcircuits.com/showthread.php?t=2687&highlight=ripple+filter
I found a pi filter calculator too @ http://www.calculatoredge.com/electronics/ch pi low pass.htm
I have no clue what values to put in, can someone please explain this to me? im assuming a cutoff value would be really low to filter off everything from just above DC and up. or can 1 stage be for 60hz hum and a second stage for ripple at 120hz?
i dont have a true rms meter or an ocilliscope, but here are the specs: 120v/60hz in 30vac/60hz out of the transformer. 25 amp bridge rectifier, regulator is adjustable from 3-25 volts up to a max 15 amp load( ive added a 3rd power transistor in parallel to the circuit) Thank you so much! Joe
I found a pi filter calculator too @ http://www.calculatoredge.com/electronics/ch pi low pass.htm
I have no clue what values to put in, can someone please explain this to me? im assuming a cutoff value would be really low to filter off everything from just above DC and up. or can 1 stage be for 60hz hum and a second stage for ripple at 120hz?
i dont have a true rms meter or an ocilliscope, but here are the specs: 120v/60hz in 30vac/60hz out of the transformer. 25 amp bridge rectifier, regulator is adjustable from 3-25 volts up to a max 15 amp load( ive added a 3rd power transistor in parallel to the circuit) Thank you so much! Joe
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