I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked + AC -
with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center. What
do I do with the transformer three and four on the bridge?
Thanks for any help to a dummy; Don

On Sun, 29 May 2005 10:19:32 -0400, "dwbauer"
wrote:

I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked + AC -
with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center. What
do I do with the transformer three and four on the bridge?

---
Connect the yellow wires to the AC terminals of the bridge and either
cut off the center tap or cut off the exposed conductor and tape the
wire back out of the way so it won't touch anything that gets hot.
Connect the + terminal of the bridge to whatever was connected to the
+ terminal of the old bridge and connect the - terminal of the bridge
to whatever was connected to the - terminal of the old bridge.

I don't know what you mean by:
"What do I do with the transformer three and four on the bridge?".

--
John Fields
Professional Circuit Designer

Terminals labeled AC on the rectifier bridge are connected to the ac source,
your transformer. The + and - are connected to the filtering circuitry and
eventually the load. Pay attention to the polarity of the + and -
connections, as to where the originals were connected. With your
transformer, as noted, connect the yellow leads to the AC terminals of the
rectifier bridge. Isolate and insulate the centre lead.
"John Fields" wrote in message
...
On Sun, 29 May 2005 10:19:32 -0400, "dwbauer"
wrote:

I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center
tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked +
AC -
with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center.
What
do I do with the transformer three and four on the bridge?

---
Connect the yellow wires to the AC terminals of the bridge and either
cut off the center tap or cut off the exposed conductor and tape the
wire back out of the way so it won't touch anything that gets hot.
Connect the + terminal of the bridge to whatever was connected to the
+ terminal of the old bridge and connect the - terminal of the bridge
to whatever was connected to the - terminal of the old bridge.

I don't know what you mean by:
"What do I do with the transformer three and four on the bridge?".

--
John Fields
Professional Circuit Designer

That worked great!
Thanks, so very Much; Don
"John Fields" wrote in message
...
On Sun, 29 May 2005 10:19:32 -0400, "dwbauer"
wrote:

I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center
tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked +
AC -
with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center.
What
do I do with the transformer three and four on the bridge?

---
Connect the yellow wires to the AC terminals of the bridge and either
cut off the center tap or cut off the exposed conductor and tape the
wire back out of the way so it won't touch anything that gets hot.
Connect the + terminal of the bridge to whatever was connected to the
+ terminal of the old bridge and connect the - terminal of the bridge
to whatever was connected to the - terminal of the old bridge.

I don't know what you mean by:
"What do I do with the transformer three and four on the bridge?".

--
John Fields
Professional Circuit Designer

On Sun, 29 May 2005 15:44:34 -0400, "Art"
wrote:

Terminals labeled AC on the rectifier bridge are connected to the ac source,
your transformer. The + and - are connected to the filtering circuitry and
eventually the load. Pay attention to the polarity of the + and -
connections, as to where the originals were connected. With your
transformer, as noted, connect the yellow leads to the AC terminals of the
rectifier bridge. Isolate and insulate the centre lead.

---
I guess that's somehow different from what I wrote earlier?...

"John Fields" wrote in message
.. .

---
Connect the yellow wires to the AC terminals of the bridge and either
cut off the center tap or cut off the exposed conductor and tape the
wire back out of the way so it won't touch anything that gets hot.
Connect the + terminal of the bridge to whatever was connected to the
+ terminal of the old bridge and connect the - terminal of the bridge
to whatever was connected to the - terminal of the old bridge.

--
John Fields
Professional Circuit Designer

no Pun, John: Sometimes repetitive info connects?? Duh: Have a fine
Holiday
"dwbauer" wrote in message
.. .
That worked great!
Thanks, so very Much; Don
"John Fields" wrote in message
...
On Sun, 29 May 2005 10:19:32 -0400, "dwbauer"
wrote:

I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center
tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked +
AC -
with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center.
What
do I do with the transformer three and four on the bridge?

---
Connect the yellow wires to the AC terminals of the bridge and either
cut off the center tap or cut off the exposed conductor and tape the
wire back out of the way so it won't touch anything that gets hot.
Connect the + terminal of the bridge to whatever was connected to the
+ terminal of the old bridge and connect the - terminal of the bridge
to whatever was connected to the - terminal of the old bridge.

I don't know what you mean by:
"What do I do with the transformer three and four on the bridge?".

--
John Fields
Professional Circuit Designer

Look carefully at your bridge rectifier - the AC input & DC outputs are
almost always clearly marked.
The DC polarity will be marked, but if you can't be sure the longest output
pin is by comvention DC +
Remember AC is sometimes labelled by a "wiggly line".

The transformer is best examined IMHO using a "multmeter" (test meter) set
to AC in the voltage range 0-20 or whatever is most suitable to measure
around 12 VAC on your meter.
I would expect you can confirm the two terminals most distant apart (IE
excluding the centre tap terminal) will show you the higher voltage you
seek.
I can't quite recall if the AC RMS voltage will read 12 or about 14.5 but
after rectification & some smoothing you should see 12VDC.
Pete


Check the output terminals first
"dwbauer" wrote in message
. ..
I am attempting to replace a bad transformer in a 12v battery charger. I
went to Radioshack and purchased a 12v transformer and a 4 amp full wave
bridge, but I don't know how to connect it. The transformer is center
tapped
Primary is 120v Secondary is - 6.3 - 0 - 6.3, 3a the bridge is marked +
AC - with four leads (|=leads)
e.g. | + | | AC | - |
I have three leads from the transformer, two yellow and a black center.
What do I do with the transformer three and four on the bridge?
Thanks for any help to a dummy; Don