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PWM

Discussion in 'Wiki' started by derekleffew, Sep 5, 2008.

  1. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Pulse Width Modulation. A method of controlling power by rapidly switching on and off. The ratio of on time (the pulse width) to off time determines output power. IE, starting with 12V, a PWM value of 50% provides an effective output of 6V, 75% 9V, etc.

    Used in switch-mode power supplies and sine wave dimmers (typical frequencies 40-400 kHz, and quite often for LED control in a color mixing fixture (typical frequencies around 1 kHz). Also used by Variable Frequency Drives and sine wave inverters to create a sine wave from a DC bus.
     
    Last edited by a moderator: May 25, 2010

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