Full bridge rectifier calculation issue

155

04:03:47

According to my calculations, a 311V peak AC input should yield 198V DC after being rectified and smoothed yet in the simulation the value is much higher? Can anyone explain what went wrong?

published 5 years ago

PrathikP

5 years ago

It seems to be some transformer related weirdness. Reduce the transformer primary inductance from the default 10H to something more becoming, like 1H and you will get the right results for an unloaded output.

PrathikP

5 years ago

If you want to keep the 10H inductance, load the output with 10k resistor (never leave the output of such circuits unloaded. You must load it to ensure that the capacitor discharges and also the diodes don't stop conducting)

fatcat2

5 years ago

Seems to be some clamping action.

PrathikP

5 years ago

Not really. Then the voltmeter would read 620V (310*2)

fatcat2

5 years ago

Is this a bug?

PrathikP

5 years ago

Most probably

gahtan

5 years ago

Tested it again without a transformer and this time by adding a 10k resistor on the output and it seems that the app have some problems with capacitive smoothing. When i removed the capacitor it has an accurate waveform oscillating between 0V and 309V but when I added the capacitor the DC output voltage sticks at 309V which is much higher than the overall mean voltage of 198V. Either this app is buggy or I need to improve my knowledge on capacitator smoothing.

fatcat2

5 years ago

This app is buggy

BillyT

5 years ago

The smoothing depends on the loading, IE; With a 1 mF capacitor and a 10k load the DC output will be almost the full Peek Voltage. With a 1k load the voltage will be closer to 289Vdc. http://everycircuit.com/circuit/4907178966908928

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