I have a doubt that instead of rectifier we can use positive clamper to get the DC voltage at output, because the clamper adds the DC voltage to the AC signal, but even the same thing is done by the rectifier.

So can you please explain why can't we use the clamper for outputting DC from AC?

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    \$\begingroup\$ Please, add the schematics of the circuits you are referring to. People here don't usually want to waste time guessing what exact circuit you have in mind (clamper and rectifier are quite generic terms). \$\endgroup\$ – Lorenzo Donati -- Codidact.com Jul 3 '17 at 8:19
  • \$\begingroup\$ clamper adds the DC voltage to the AC signal even the same thing is doing by the Rectifier Not true, a rectifier only lets the positive (or negative) part of the signal through. A clamp prevents the signal from going above (or under) a certain value. After a rectifier you do not know anymore what the negative (or positive) part of the signal looked like. After a clamp you do not know what the signal looked like above (or under) a certain value. A rectifier "works" around 0 (zero) volt, a clamp can work on any level you design it to. \$\endgroup\$ – Bimpelrekkie Jul 3 '17 at 8:22

You can use a clamper to produce a waveform that has an average value that is approximately the peak value of the AC waveform but you'll still need a diode and a capacitor to smooth that to a DC supply capable of being useful. Then you'll get a smooth DC supply voltage that is approximately the peak-to-peak value of the AC waveform.

Incidentally, this method is used in the cockcroft walton multiplier: -

enter image description here

So can you please provide why cant we use the clamper for output DC from AC?

You can as per the example of the cockcroft walton voltage multiplier.

Another example of using a clamper to get a DC level is when dealing with a small AC signal such as from an audio line out: -

enter image description here

With just a few hundred mV RMS to play with, a DC level can be produced that is sufficient to turn on a MOSFET (such as a BSH103) and drive a relay. The two diodes and two capacitrs form exactly the same circuit as the 1st stage of the cockcroft walton multiplier shown above.

  • \$\begingroup\$ Can we obtain Only DC from clamper other than AC through smoothing and without the help of Rectifier? \$\endgroup\$ – Eswara Srisai Jul 6 '17 at 11:27
  • \$\begingroup\$ If you use an inductor and smoothing capacitor you can get some increase in DC but only about half of what you get from a diode and capacitor added to the clamper. \$\endgroup\$ – Andy aka Jul 6 '17 at 11:31
  • \$\begingroup\$ @EswaraSrisai the best thanks you can give is to upvote and/or accept an answer. \$\endgroup\$ – Andy aka Jul 6 '17 at 11:45

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