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Old 26th Aug 2010, 9:27 am   #25
ppppenguin
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Location: North London, UK.
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Default Re: Old car radio - how to change polarity?

Since the input and output are totally isolated from each other you can think of the DC-DC converter as a separate battery, dedicated to running the radio. Hence you can connect the radio chassis to the car chassis, then power the radio from a "battery" with whichever polarity it needs.
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