Sirius radio car dc power

Discussion in 'General Electronics Chat' started by big jim, May 31, 2009.

  1. big jim

    Thread Starter New Member

    May 31, 2009
    3
    0
    What's inside the cigarette lighter adapter that steps down 12 volt dc to about 5 volt dc for the Sirius radio? What's the electronics/schematic? If I guess the current of the radio at 0.5 amps and a voltage drop of 7 volts then using Ohm's law I need a series resitor of 14 ohms at 3.5 watts.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    It's probably a "buck" type switching regulator. They're very efficient.
     
  3. radiohead

    Active Member

    May 28, 2009
    474
    31
    Since it's restricted space, it's probably an SMT circuit centered around the LM 7805 +5V regulator.
     
  4. big jim

    Thread Starter New Member

    May 31, 2009
    3
    0
    Thanks radiohead,
    What's the schematic for "buck" type switching regulator SMT circuit LM7805 +5V regulator?
     
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