What Pot to use for LED Dimmer?

Discussion in 'General Electronics Chat' started by 222fbj, Apr 27, 2009.

  1. 222fbj

    Thread Starter New Member

    Apr 27, 2009
    I built a few LED lights using various types of LEDs. I would like to add a pot (on/off and dimmer). How do I go about determining what pot(s) are appropriate?

    I have done some price/shopping for pots and they range from $2 to 'too much$$$'. Hopefully there is an inexpensive Pot that will work for me.

  2. Wendy


    Mar 24, 2008
    What is your power supply? You can use almost anything, but you have to match it to what you have.

    Have you read this?

    LEDs, 555s, Flashers, and Light Chasers

    Pay special attention to the first chapter, and figures 1 and 2, to understand LEDs. You will need a minumum resistor, say 100Ω (but it depends on the power supply) to set the maximum current. A 5KΩ pot will adjust it down from there, even a 1KΩ might work, and a 10KΩ will have a lot of dead range.
  3. ruleworld


    Jun 9, 2006
    if u have a high source like 12v then always use a series resistor(about 1Kohm) else the LED will burn when u turn the pot value too low.
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Pots with switches are not as plentyfull as without, and most do not give wattage. Try for 1/4 W or higher. ' found an example: All Electronics Cat # LTPS-20k $ .75 US 20kΩ, with switch +postage. 5k-10k would be my choice. For full-range control connect pot across power supply, cathode of LED to neg, anode to 510Ω , other end to wiper.[ assuming a 20 mA LED].
  5. SgtWookie


    Jul 17, 2007
    The one item that's missing from Bill Marsden's link would perhaps be the most useful in your case.

    That's a 555 timer PWM circuit. A 100k pot is quite useful for such circuits.