SCR gate current sinewave

Discussion in 'Homework Help' started by ShowerOf, Nov 18, 2009.

  1. ShowerOf

    Thread Starter Member

    May 4, 2009
    Hello, I have a question regarding the gate current sine wave of an SCR

    I am asked to sketch the output voltage on top of the supply voltage waveform and the required gate current below it when the SCR delay angle is 45°

    I have sketched the output voltage sine wave, but the gate current sine wave I am not sure about.
    I think there will be a positive rise in gate current until the trigger current is reached and the SCR turns on and then the gate current decreases to near 0.

    My output voltage sketch is similar to the sine wave in this image

    Where the black line wave is the output voltage and the red line is the
    AC source.

    I have been trying to find a gate current sine wave image to compare with
    it. Can any one describe the gate current wave form or give a link to an image of such?

    Any suggestions for programs to draw sine waves?

    Attached is a circuit similar to that shown with the question.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. ShowerOf

    Thread Starter Member

    May 4, 2009
    Thanks, I have looked at that chapter and the link for the image
    in my post is from that page.

    I am guessing now but will the gate current look similar to the portion
    missing from the positive output voltage sine wave?