Full wave rectifier from a wall wart?

[steve_j83]

ahhh thanks Hero!

Yeah forumlicker i was thinking about that one but hero's one has a single pot to control both voltages which is more convinent for what im doing, looks like he has put alot more work in to make it a nice clean supply too.... plus he has supplied the pcb art work on another thread which makes my life much easier.

Hero any chance i could get a copy of the art work with the components on it as i cant quite place a few of them.

 

[forumlicker007]

Yeah forumlicker i was thinking about that one but hero's one has a single pot to control both voltages which is more convinent for what im doing

Which pot you refers to..

 

[steve_j83]

on hero's?

R7 edit:not labeled r7 on that one.... the 2k5

https://www.electro-tech-online.com/threads/variable-bipolar-power-supply.24291/

 

[tcmtech]

Most of the wall power packs I have taken apart that had a center tap transformer used a half bridge design for the rectification. They still were the standard two wire cord.
Allthough I have takes several medical application ones apart. They all had a three or four wire cords with one of the spare wires as a ground.
The four wire ones I have found had two wires for a AC output and the third was the DC output. The fourth wire wa sthe ground and the DC return line going to both the center tap and the ground.

 

[Hero999]

That makes sense.

The centre tapped transformer plus two diodes is just a biphase full wave rectifier.

The medical wallwart is probably really expensive and specifically designed for the device powered by it.

The voltage doubler circuit I posted is designed for an AC wallwart unit, not just the transformer.