# half-wave rectifier

Discussion in 'Homework Help' started by edd grog, Nov 16, 2008.

1. ### edd grog Thread Starter New Member

Nov 16, 2008
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6) If the A.C. input frequency to a half wave rectifier is 120 Hz what is the frequency of the residual A.C. in the output.

could some one please give us a help in the right direction. am i right in belivein this is simply half the frequency (60) or still 120 hertz with the negative part of the waveform being 0 volts?

2. ### beenthere Retired Moderator

Apr 20, 2004
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Take an AC waveform and remove all of the negative going portion? Has the frequency changed? You might notice that it is no longer AC in nature.

3. ### anakdandan New Member

Nov 13, 2008
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i have the same homework and base on my research :

fout = fin
therefore there is no change in frequency in terms of rectification whatever it may be.

so it is still 120hz

4. ### mik3 Senior Member

Feb 4, 2008
4,846
63
No, its not 120Hz. If the mains frequency is 60Hz then the rectified output voltage will have a frequency of 60Hz for a half wave rectifier.
Note that the 60Hz rectified output is not a sinewave, its a sinewave with its negative parts removed, but because its a periodic signal if you measure the time between two equal value points and find the inverse of this time then you get the frequency of the rectified signal. By coincidence its the same as the mains frequency.

5. ### JoeJester AAC Fanatic!

Apr 26, 2005
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The question read ...

So the answer remains f out = f in for half-wave rectifiers.

Apr 5, 2008
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7. ### keviiii New Member

Oct 17, 2008
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hi, may i know under wad circumstances will the output frequency be not the same as the input?

thanks. cuz i think i was taught that the output frequency will be the same as the supply frequency.

ha. please tell me my instructor is wrong. hahaha.

thanks.

8. ### mik3 Senior Member

Feb 4, 2008
4,846
63
If you have a half wave rectifier then the output waveform has the same frequency as the mains (line) frequency. If you have a full wave or a bridge rectifier then the frequency of the output waveform is twice the mains (line) frequency.

9. ### keviiii New Member

Oct 17, 2008
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yup. consistent to wad im taught. haha. thanks man.