Why do all power supplies use ct transformer instead of a bridge rectifier

Thread Starter

chucknnc

Joined Feb 12, 2015
4
I am retired now and for as long as I can remember all linear power supplies use a center tapped transformer instead of no center tap and a bridge rectifier. I understand back decades ago rectifiers were expensive so they used a CT transformer so only 2 diodes were needed, but now with ultra cheap diodes why do they still go to the expense of CTapping a transformer winding and bring it out to a terminal.
 

crutschow

Joined Mar 14, 2008
23,480
On possible advantage is that you lose only one diode-drop instead of two.

On what sample of designs do you base your assumption that all use a CT transformer and no bridge?
 

MrChips

Joined Oct 2, 2009
19,373
1) CT transformer is not more expensive to manufacture.
2) PSU with either configuration are commonly used.
3) Voltage drop and power loss in diode is reduced with CT xfmr.
4) Current output is greater with CT xfmr.
 

Thread Starter

chucknnc

Joined Feb 12, 2015
4
I have been repairing battery chargers and Amateur radio high current power supplies for decades, so I guess the .6v drop from extra diode maybe the answer.
 
Top