Bridge rectifier vs Full wave rectifier

[hilbert_mostert]

Hi There,


After seeing a lot of different schematics I've noticed that a lot of schematics still use a full-wave ( two diodes ) rectifier and others a bridge. For what I've seen is that most of the schematics use the full-wave version.

What are the pro's and cons of using a conventional rectifier to a bridge rectifier ( and vice versa )?

From what I know is that a bridge rectifier is able to almost double the voltage which should result in smaller transformers but is there a catch which I dont know about?


Regards,

Hilbert

[Colt45]

A bridge is simply two fullwave circuits... So.. fullwave has the advantage of having half the diode drop.

Where the benefit lies is, half the voltage, half the windings... (albeit thicker ones).

double the windings, or double the diodes... in the tube days, copper was cheaper and quite more efficient than running double the rects (1-2 tubes instead of 3-4, so less tubes, sockets, heater costs... and double a 30v drop makes more of a problem than double a 0.7v drop). Now with diodes for cents, they're much cheaper.

[Tom Bavis]

Bridge or voltage doubler has better transformer utilization, since all the copper carries current for the full AC cycle. Full-wave (half-bridge) carries current only half the time for each half of the winding. So if you're having a custom transformer made, it can be 30% smaller or give 40% more output or 30% better regulation if you use a bridge or doubler. If you're using or selecting an existing transformer, you will use whatever it's designed for - probably center-tap full-wave.

[pointy]

fullwave came in to use as it was light to carry (gig amps etc.....)

[Jeb-D.]

From what I know is that a bridge rectifier is able to almost double the voltage which should result in smaller transformers but is there a catch which I dont know about?

Current demand from the transformers winding has doubled (as a rough approximation)

So the transformers voltage requirement has halved, but the current demand of the remaining winding has doubled. The required VA of the transformer is pretty much the same for either form of rectification.

For the most part, people just use whatever configuration that gives desired output with an available transformer.

Perhaps it takes less copper to do a transformer for a bridge, but I'm unsure. You only need half the windings, however, the wire gauge must be thicker to get an equivalent I2R loss. It may balance out from this aspect as well.

If using tube rectifiers, full-wave is easiest.