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Question about LED lighting?

I am wanting to hook up these LED lights however they always burn out because of the high voltage and amperage from the source. I have LEDs that run on approximately 3DCV max and are 0.03 amps max, my source is an intermittent 7ACV max (a.k.a. an on off DC current and yes it does work but not with the LEDs I want) So I want to know what resistors(possibly 100 ohms?) and other electrical components I need to use so that the LEDs I want to use will not burn out in a matter of 5 minutes or less.

Public Comments

  1. "intermittent 7ACV max (a.k.a. an on off DC current)" Pulsated DC isn't AC so the description needs clarifying. This link http://led.linear1.org/led.wiz is an easy guide to figure the resistance values given the values you have. The guide even shows you how to wire it up.
  2. you can use this
  3. Your LED's have an effective DC resistance of 100 ohms (3v @ 30ma). Which mean another resistor in line would have to drop 4v or 33% more than your LED's 3v drop. So you'd need a 133v resistor. A standard 150 ohm resistor will do the job. AC or pulsating DC voltage source has little effect other than causing your LED's to flicker.