A wealth of information here and I'm excited to now be a part.
I have a small transformer model: DB41X26.5 120V AC TO 14.5V aC
Would like to add a rectifier circuit to it so I can use use it to power a dc project device. PLease, please, please forgive a guy like me who is somewhat new and trying to move forward into the more technical stuff other than just wires etc. Anyone have an idea for a rectifier circuit or is there anything they can be taken out of, like maybe a computer power supply?

 

What DC voltage and current do you need?

 

12-14VDC at 4 amp maximum

 

...is there anything they can be taken out of, like maybe a computer power supply?

Yes absolutely, but I wouldn't disable a PSU to build another supply, since an old PSU can make a great benchtop power supply. And all but the oldest PSUs will be switch-mode anyway, and not as good a source of diodes or rectifiers.

You can find rectifier diodes in many, many other old electronics such as radios, TVs or VCRs. Just look for the biggest diodes near where the AC power comes in, usually near a transformer. Occasionally you'll even find a single component rectifier, a square device with the 4 diodes already built in. And you can always build a rectifier out of 4 identical diodes.

But you'll soon be back to crutschow's question: Just making a rectifier is easy, but assuming you want to actually power something, you need to know the current load or you risk frying your diodes. Your diodes will need to be rated to 20v or more, but that shouldn't be much of a problem. Don't forget to put a fuse on the primary (AC side) of the transformer.

 

4A is more than you will easily find in most devices unless the device has a big motor, such as a paper shredder (typically 5A rectifier or more).

 

thanks a bunch, I'm on the hunt now

 

I've noticed on power ac/dc adaptors that the secondary has 3 taps on it. is one tapped into the center of the secondary? if so what for?

 

some info on rectifier design, look here
you will see center tap design
http://www.allaboutcircuits.com/vol_3/chpt_3/4.html