pitts_pilot(at)bellsouth. Guest
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Posted: Sun Apr 30, 2006 1:22 pm Post subject: stepping down from the bus voltage |
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GOLDPILOT(at)aol.com wrote:
Quote: |
<<I am thinking the installer must have installed some form
of step-down transformer to feed the unit 6VDC (or installed the cigarette
lighter plug behind the panel). >>
You can not use a transformer on DC. Doesn't work that way. You would need
to find out how much current the device draws and then calculate the
resistance needed to drop X-amount of voltage across the resistor. The rest of the
voltage is used by the device.
David
A lot of the DC>DC converters that plug into a cigar lighter use a
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linear regulator to drop the voltage ...... while some have a pretty
neat (and tiny) switching power supply in there!!!
David failed to mention the REASON transformers don't work on straight
DC. A transformer needs AC in the primary to cause the magnetic flux in
the core to change polarity so those 'lines of force' can cut through
the coil in the secondary, and thereby induce the current in the
secondary. And for the purists .... yes, you can pulse the DC, but it's
crude and inefficient.
If you got this far and don't really care .... well, it's too late!!!
That's the rest of the story.
Linn
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