LED driver

Discussion in 'General Electronics Chat' started by tilottama, Mar 10, 2011.

  1. tilottama

    Thread Starter New Member

    Mar 10, 2011

    i want a led driver circuit with intensity control
    basically there are 3 leds each havng a pot...
    and 9 v supply is given...n wht is the power watt...
    n i also want 5 milliwatts led driver circuit...same as above

    soo can any 1 help me out wid ths.....

    my gmail <snip>
    Last edited by a moderator: Mar 10, 2011
  2. Wendy


    Mar 24, 2008
    Welcome to AAC.

    Show us your schematic. it is a standard request.

    Since these are low power LEDs you can use a pot. With a true high power LED, the kinds that take 350ma, or 700ma, or even 1.4 amps this is not the case. However, the little details you gave suggest 20ma.

    LEDs are current controlled devices, but you have to exceed the dropping voltage before the current can do its job. Different colors use different voltages, 2.5VDC for a red LED, or 3.6VDC for a blue or white LED. These voltages are approximations, the exact voltage is in the LEDs datasheet.

    If you try 3 white LEDs at 3.6 volts in series you will need 10.8V, more than a 9V battery can provide.

    I have an article for beginners, it starts off explaining LEDs in detail, then goes up from there.

    LEDs, 555s, Flashers, and Light Chasers