How many 0.25W led lamps can be connected to a 12V 500mA adapter?

Answer 1

The LED lamp consists of the LED and some circuitry that allows it to work at 12 volts. The wattage of your supply is volts x amps. 500 ma = 1/2 amp so you have 6 watts available. So doing the math and dividing 6 by .25 you could run 24 of the lamps. Now depending on the supply it might run hot if on continuously so you might have to drop off a few lamps.

Answer 2

You can connect up to 4 0.25W LED lamps to a 12V 500mA adapter. Each lamp would draw about 62.5mA of current. So, 4 lamps would draw a total of 250mA which is within the capacity of the 500mA adapter.