bridge rectifier output

[najnielkp]

hi all, i am building my power supply and using 400v 50 amp bridge. i have 112v ac input to it, but only get 100v dc out. do some bridges reduce voltage ? i was expecting 112v x 1.4 = 156v.

[gar]

060710-0702 EST USA

najnielkp:

The RMS value of a sine wave is 0.707 of the peak. The average voltage of a full wave rectified sine wave is 0.636 of the peak. 0.636/0.707 = 0.900. 112 x 0.9 = 100.8. Then there is a slight diode drop. So you are getting exactly what is expected.

Put an appropriately large filter capacitor on the bridge output and you will get approximately the peak of the sine wave. 112/0.707 = 158. Note 1.414 is the square root of 2, and .707 is 1/2 the square root of 2. Use calculus to calculate the RMS and average relations to the sine wave peak.

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[Madclicker]

Put a filter cap on it and you will probably see the right number. The output of the bridge is still an ac signal until you store it in a cap.

[najnielkp]

thanks for all your replies.