I am doing a low energy nuclear reaction experiment and i have a 130V 3A variac plugged into just a standard wall socket then i have a 1000W 2 to 1 step transformer plugged into my variac. and then i have a set of electrodes in heavy which are connected to a full wave bridge rectifier which then are plugged into the step up transformer. for this experiment to work i need a constant voltage going to my electrodes. So my question is do i even need a smoothing capacitor after the full wave bridge rectifier, and can i buy full wave bridge rectifiers with a smoothing capacitor built in or do i need to buy capacitor, if so how big or i also read you can make a parallel series of capacitors if so how many and how big. Thanks
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No, you need to get a separate capacitor. And the size depends on how much ripple you want. You cannot get it to zero or even close with just a cap.
If you want 0.1 volts P-P of ripple, for example, and assuming this is at 60 Hz. then use
CV = it
C = it/V = (5)(8ms) / 0.1 = 400 mF or 400000 µF at 450 or 500 volts. That is a very large capacitor.
But again, you need to define how much ripple is OK.
Perhaps if you mentioned the actual application, i can guess at the ripple needed.
If you want 0.1 volts P-P of ripple, for example, and assuming this is at 60 Hz. then use
CV = it
C = it/V = (5)(8ms) / 0.1 = 400 mF or 400000 µF at 450 or 500 volts. That is a very large capacitor.
But again, you need to define how much ripple is OK.
Perhaps if you mentioned the actual application, i can guess at the ripple needed.
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You can't get over 2000 watts from a 130 VA transformer.