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As in the question title. Is it possible to generate basic dual rail power from two bridge rectifiers? I tried wiring one forwards and one backwards in a simulator, but I found that it did not work. Does anyone know if it's possible? Instincts say no, because it would require doubling the supply voltage, and that's tricky with just diodes.

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  • \$\begingroup\$ So, what did you end up doing? \$\endgroup\$ – drxzcl Mar 10 '11 at 22:49
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If the bridge rectifier follows a transformer, and the transformer has a center tap, then the center tap is at the middle (ground) potential. This is the standard linear power supply fpr hifi amplifiers or to make +/-15V for op-amps.

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There's no such thing as a "backwards" bridge rectifier, it's just a regular rectifier with the schematic laid out in the mirror. Therefore, you would get exactly the same voltage levels from both rectifiers.

What you obviously could do is use a single rectifier, and then split the voltage to make a virtual ground.

Another option is to use two half-wave rectifiers instead of bridge rectifiers, with large caps to smooth out the blank sections. This would likely yield less voltage overall, but should be workable.

Yet another option is to use a voltage doubling rectifier and tap a virtual ground off the middle of the doubling ladder.

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  • \$\begingroup\$ Of course, splitting the voltage would dissipate a lot of power, unless some kind of switch-mode splitter (if such a thing even exists) was used. \$\endgroup\$ – Thomas O Feb 18 '11 at 13:28
  • \$\begingroup\$ See my edit about half-wave rectification, that should be less wasteful. \$\endgroup\$ – drxzcl Feb 18 '11 at 13:37
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    \$\begingroup\$ ti.com/product/tle2426. Of course, there are cheaper ways to do it, as well. \$\endgroup\$ – Scott Seidman Feb 26 '13 at 12:07
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Yes it is:

enter image description here
(source)

I didn't know about this before, but you can make a split rail PSU this way - from a single bridge rectifier. Tap off the center as ground and you've got a positive and negative rail from the caps.

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  • \$\begingroup\$ This is a standard voltage doubler when the switch is closed. The lower diodes do nothing. \$\endgroup\$ – markrages Apr 12 '17 at 18:22

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