Dual Secondary transformer wiring question.

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stephenl
Posts: 383
Joined: Wed Aug 13, 2008 10:21 pm
Location: Clinton, MA

Dual Secondary transformer wiring question.

Post by stephenl »

Stupid question but I'm having a slight brain cramp. If I wire a dual secondary in series, can I use the the two wires that I tie together as a centertap feeding a full wave center-tapped rectifier? With them wired as such, I have 20vac going into the rectifier (10vac on each side of the tiepoint) and I get 1/2 the expected dc voltage on the output.
Steve
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Phil_S
Posts: 6048
Joined: Tue Oct 23, 2007 10:12 pm
Location: Baltimore, MD

Re: Dual Secondary transformer wiring question.

Post by Phil_S »

You almost have it. You can wire in series and create a center tap. Make sure you wire them in phase or you will have 0 volts where you expect 20.

Actual voltage output depends on the type of rectifier. In a perfect world using a full wave bridge with cap input, with solid state diodes (the kind where the schematic shows 4 diodes in a diamond shaped format), you should get 20VAC * sqrt(2) = ~28VDC. DC current will be about 62% of AC current.

The laws of nature state you can't get something for nothing. As you increase voltage, current capacity will drop and vice-versa.
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