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Old 10th August 2012, 02:51 AM   #1
mbeards is offline mbeards  United States
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Default Transformer center tap question

Hi everyone,

So I am installing a VU meter on my amplifier the I got of ebay.

The vendor also sells the power transformer to drive the board. The board requires 24V and the transformer is 12-0-12V So i will use the two 12V taps to power the board. Now normally I know that with a full bridge rectifier, you don't use the center tap on the transformer. It would short the secondary since the full bridge is usually referenced to ground.

However with the VU driver board's bridge is not referenced to ground anywhere since the board is all self contained. It is rectifying the 24V AC from the transformer aka the two 12V taps with the low side of the rectifier ungrounded.

In this instance, should the center tap be used to reference that circuit to ground somewhere too keep it from floating?

Sorry for the poor explanation,

Matt
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Old 10th August 2012, 05:00 AM   #2
Junm is offline Junm  Philippines
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using th 12vac in series is 24 volts going to the board...don't use the center tap since one terminal will refer to ground....not unless there's a need for + and - rails...
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Old 10th August 2012, 06:01 AM   #3
AJT is offline AJT  Philippines
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check to see what your vu meter board require i mean B+...
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Old 10th August 2012, 04:16 PM   #4
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Let the circuit float - it will be grounded when it's connected to a circuit for measurement. Ground any other point and it may introduce a ground loop.
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Old 10th August 2012, 06:00 PM   #5
tomchr is offline tomchr  United States
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Leave the center tap floating. Cut or tape/heatshrink the wire to ensure it doesn't accidentally touch the chassis or any component of the amp.

~Tom
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