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In the Forum: Audio Discussions
In the Thread: It’s mad, mad, mad... electricity.

Post Subject: An isolated example of misunderstanding isolationPosted by Bud on: 7/15/2009

All switch mode power supplies that receive a CE, UL or CSA approval have complete
isolation from the wall voltage, across the dielectric barriers of a transformer, from primary
to secondary.

The isolation of noise occurs because the incoming wall voltage is converted to DC before
anything else happens. Then it is chopped up into high frequency pulses, fed through the
transformer and reconstructed on the other, secondary side, into a sine wave.

This is then fed to your down stream equipment. Also rectified, from another lower voltage
tap from the transformer, is the DC used to charge the battery and to float that charge to the
battery until the wall voltage disappears.

When the wall voltage disappears, the chopper circuit, which only ever sees DC, is fed from
the Battery rather than the rectified voltage from the wall. The actual DC voltage is immaterial here,
the only important thing is that there is enough total VA from the battery to allow the unit to provide
the rated power as a reconstructed AC wave form, from the output.

The units will run just fine with a completely useless battery, as a noise isolation device, but not
as an APS device. I would not guarantee they will run just fine without any battery and I STRONGLY
suggest you contact tech support before you attempt to do this.

Bud

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