Power Supply for RF Modulator

Discussion in 'The Projects Forum' started by CircuitSurfer, Mar 10, 2010.

  1. CircuitSurfer

    Thread Starter New Member

    Sep 19, 2009
    21
    0
    Hi I need a power supply for my project. I intend to take the plug off the the phone charger but I have no multimeter to know which line is positive. One of the two wires have a white stripe running on top of it. Would that be the positive?
     
  2. ziouranio

    Member

    Jul 23, 2009
    20
    0
    I have experienced both cases where the white strip indicates the positive and cases where the strip is on the negative.... the only way to be sure is to use a multimeter and check.
     
    Last edited: Mar 10, 2010
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Here is a simple and cheap low voltage polarity checker you can build:

    [​IMG]

    The probes can be just plain wire.

    Both LEDs need to be in the circuit, as they protect each other from excessive reverse voltage.
     
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