I've been wondering why bridge rectifier provides better significance and is mostly taught everywhere in universities rather than a similar circuit that uses two diodes in parallel instead of four.

Two-diode model of a full wave rectifier

FWR with 2 diodes

Bridge rectifier

enter image description here

I observed the I/O and time domain characteristics (I am using the constant voltage model instead of the exponential model for simplicity of analysis), only to find that the output voltage of the bridge wave rectifier conducts after 2VD-ON (VD-ON = standard voltage necessary for diode to conduct) whereas in the two diode system it conducts right after VD-ON as only one diode is conducting in forward or reverse bias (similar to a half wave rectifier.) The image below shows the I/O characteristics of bridge rectifier in constant voltage model.

I_O Bridge rectifier

The time domain characteristics with constant sine signal input voltage is as below.

enter image description here

Though I know that in practical cases VD-ON is not significant, I'm confused why the bridge rectifier is more celebrated than the two diode version of the full wave rectifier.

  • 6
    \$\begingroup\$ That circuit you posted isn't a rectifier. Current runs in both directions through R. \$\endgroup\$
    – Janka
    Commented Apr 20 at 20:19
  • 2
    \$\begingroup\$ No, it only goes in one direction. That's what makes it a rectifier. \$\endgroup\$
    – Finbarr
    Commented Apr 20 at 20:36
  • 4
    \$\begingroup\$ In your two-diode circuit across R is an AC voltage. \$\endgroup\$ Commented Apr 20 at 20:38
  • 2
    \$\begingroup\$ @Adiji007 Please quote the website from where you copied the image (not everyone might know that website, it is a good source of info). Also the diodes in your circuit are useless and more efficient without them. \$\endgroup\$
    – Justme
    Commented Apr 20 at 20:40
  • 1
    \$\begingroup\$ tinyurl.com/23cljmbg \$\endgroup\$
    – G36
    Commented Apr 20 at 20:44

1 Answer 1


How about looking at what the load "sees."

Here's a standard bridge rectifier:


simulate this circuit – Schematic created using CircuitLab

Here's the voltage across R1 to ground:

enter image description here

Here's your circuit:


simulate this circuit

Here are the voltages:

enter image description here

There's no point in your circuit where the voltage looks like the output of a bridge rectifier.

Your circuit is simply not a rectifier. At best it could be considered a clipper.


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