Earthing bridge rectifiers.

364

04:53:45

This shows the effects to the output of a bridge rectifier when you place the earth on the output of the transformer. This might not be immediately evident until the power supply is interfaced with the circuit that requires the power, it having its negative or in some cases it's positive rail grounded.

published 9 years ago

agosbcl

9 years ago

Siip joss

hurz

9 years ago

In the upper circuit its just one zero-volt-reference to much and short circuits your rectifier.

thebugger

9 years ago

Yeah first example is wrong. People don't realise there are several ground types a given system uses. An earth ground, a circuit ground, a chassis ground, also the circuit may be floating. EC has only 1 ground reference type. On the first circuit either ground the load, or one end of the transformer's secondary.

BillyT

9 years ago

@hurz & @thebugger, both of your comments are correct, the upper circuit is one that keeps on getting posted, normally with the negative in the rest of the circuit being grounded also. What the posters don't realise is that the rectification has now been converted from a bridge rectifier to a half wave rectifier. I've put a switch on the second circuit so this effect can be observed. Remember full wave rectification has a 100Hz ripple, half wave rectification has a 50Hz ripple.

thebugger

9 years ago

No, one part shouldn't be grounded, it's either one end of the transformer or one end of the bridge rectifier. Grounding both of them result in a short circuit, through one of the bridge's diodes and the maximum current is only restrained by the internal resistance of the diode (which is 100mOhm or less)

thebugger

9 years ago

Check out the current through the lower left diode of the upper circuit.

rich11292000

9 years ago

The 1st example is "what not to do" on purpose

BillyT

9 years ago

Yeah rich, I seem to have problems getting this across.

hurz

9 years ago

Because the description doesn't mentioned it?

BillyT

9 years ago

@hurz, yes I could have worded it better.

hurz

9 years ago

No problem, just add "short circuit" who cares

hsjzh

8 years ago

nice

djuz

8 years ago

обычный блок питания.

bearboy53154

8 years ago

Good example of turning a bridge rectifier into a half wave rectifier.

darkdepth

7 years ago

Thank you BillyT

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