Rectifier design - input/output voltage values

[ankireddy03]

Rectifier design

Hello sir,

I am designing 220V,4Amp DC supply using full bridge rectifier. I am using auto transformer after that isolation transformer to get variable DC voltage at output. I kept two 470uf capacitors as filter. but for 123V rms input i am getting 155V DC voltage as output. How it is possible for a low voltage ac , getting high voltage dc.
How to decide the filter capacitor value. Please help me.

 

[ravimarcus]

Re: Rectifier design

Hello sir,

I am designing 220V,4Amp DC supply using full bridge rectifier. I am using auto transformer after that isolation transformer to get variable DC voltage at output. I kept two 470uf capacitors as filter. but for 123V rms input i am getting 155V DC voltage as output. How it is possible for a low voltage ac , getting high voltage dc.
How to decide the filter capacitor value. Please help me.

DC = (AC x 1.4) - 1.2 (diode drop, can be ignored for large voltages).

So the DC voltage will be higher for a given AC voltage.

Now regarding the capacitor value, keep about 1000 uF / Amp.

Cheers

Ravi

 

[ankireddy03]

Re: Rectifier design

what is the value of AC? Is it peak value or rms value?

Added after 2 minutes:

what is the meaning of AC, is it peak value or rms value?