sage
.com...
:pacitor,
Lancaster
time in a
le at 1
put.. I
should
to
t the
ted the
. How
mind is
after my
res 25.2V
n will
but I
ide of
the
my
e the
ier
t explain this properly. I have a 24VCT transformer. The transformer need s to power 24VAC equipment as well as 12VDC equipment. For the DC circuit I first tried using a bridge directly off the 24V winding. As soon as I connected up the filter cap the DC output went to 35V, which is probably too high to feed my 12V regulator.
I then realized that I had a center tap that was not being used. So I co nnected my bridge across the center tap and one side of the secondary. Th is time the 13VAC when FW rectified using the bridge went to about 19VDC, which is a safe input to the regulator. Although this worked, I wasn? t happy about unbalancing the transformer this way so I posted my results .
e off the full secondary output with two diodes, cathodes tied together, (typical FW rectifier), and use the center tap as my negative return. I d idn't think that would make any difference in the output voltage from usi ng a bridge without the center tap however I tried it anyway. As I suspec ted it would, the DC output again went to 35V when I connected the filter up.
e is catching up with me. I guess I just don't understand the explanation of how to get a lower voltage to my DC regulator by what I thought sound ed like just configuring the transformer properly. So at the risk of soun ding like a complete idiot here can someone please explain this further? Thanks, Lenny
nfig.
iode
e uss you
ard
rd or
=/-\
=hat
Is
?config.
rll
y ove
l.
the
Until one of your zener diodes short out (a zener will eventually short out due to inrush current issues is my guess) and you then punch around
19V to the circuit that wants 12....not a good design as a result, more of a hack.John :-#(#