How do I match LEDs with the appropriate power source? Is there a sort of calculator available online?

- Jan 27, 2018 -

As usual, not enough information.

if you are wiring individual LED diodes, you have to look up the rating of the diode, the voltage at rated output and the mA rating. Different colors operate at different voltages. White is about 3.4 volts and commonly 20ma.


In a packaged unit, such as an Led strip, they wire 3 LEDs in series plus a dropping resistor to add up to 12 volts. The product ratings will tell you how many amps are required per unit. You buy a 12v power supply with enough amps to power your led units.

For an assembly with several LEDs, you wire the LEDs in series and buy an LED driver that powers that many LEDs. THe following driver powers 4 to 7 white 1 watt leds wired in series. It is a constant current (300ma) power supply that adjusts the output voltage to achieve the rated current.


For a high power cobb led module (10, 20,30,50 or 100 watt), you buy the appropriate driver.