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Weird problem in Full wave (FW) bridge rectifier

I am working on a implementation of FW bridge rectifier (without any filter). I am applying a sinusoidal input (1 Phase, +- 20, 60 Hz) to the bridge and measuring the voltage across the load resistance. When I am trying to dispaly the output waveform in a CRO, I am seeing only one half of the rectified waveform. I cross checked the individual diodes and I found that all are in perfect condition and working nice when using in HW rectifier mode. I want to know why I am seeing such a wierd results.

Reply to
dkmishra
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Are you sure you are actually measuring the voltage across the load and not the voltage from one side of the load to one side of the input? Eg. single-ended input (one scope probe) with the other side at earth.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Is the centre tap earthed?

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John Devereux
Reply to
John Devereux

If the parts are working correctly, then the circuit, simple though it is, must be wrong. Go back to the very basics and check everything - less time spent saying "it can't be" is less time wasted on the way to making it work.

Either it's wired up incorrectly, or something that looks connected is not actually connected.

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Reply to
Ecnerwal

This is the configuration I am using. (+) (-) represents the source. Now I am taking the +-10 Volt source from function generator embedded in CRO. One CRO for measurement and one for generating sine wave.

--------------------------- | | | | D D | | | | | C (+ probe RED ) (+) | | R | | R O | (-) | | (GND probe BLACK) D D | | | | | | | | | | ------------------------------

Reply to
dkmishra

Cleaning up that gibberish:

---(+)--------------------- | | | | _ _ | | ^ ^ | | (+ probe RED ) | | | C (~) (~) \\ R (Oscilloscope, in elderly TLA) | | / R O _ _ \\ | (GND probe BLACK) ^ ^ | | | | | | | | | | ----(-)----------------------

If you are feeding it a signal (~) that goes from oscilloscope ground to a positive voltage, there will be no negative part of the waveform - this is perhaps what is happening if you are using a scope probe test signal as your AC source. Try a plain old transformer. Diodes have polarity, so drawing them as "D" is not useful.

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Cats, coffee, chocolate...vices to live by
Reply to
Ecnerwal

Thanks Lawrence you are correct. Circuit is behaving as it should behave with plain old transformer. Regards Deepak

Reply to
dkmishra

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