what resistor do i need
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AnAppleSnail
Flashlight Enthusiast
Well, it'll be about 70% efficient overall. You're trying to get ~2A over 2v, so v=IR says 2=2R, so R=1.
You'll need to wire these in parallel, not series.
You'll need to wire these in parallel, not series.
Power Me Up
Enlightened
I would run each LED set off a 5W 1.8 ohm resistor:
You're wanting a 2V drop with 1.1 amp current: V = IR can be reformulated as R = V / I. 2 divided by 1.1 is roughly 1.8 ohms.
Power = VI which works out to 2.2W for each resistor.
You could possibly get away with a single 5W 1 ohm resistor but you would be getting a slightly higher voltage drop and you would be pushing the limits of the resistor. A single 10W 1 ohm resistor should work as long as you're happy with the reduced voltage and current for the LEDs
You're wanting a 2V drop with 1.1 amp current: V = IR can be reformulated as R = V / I. 2 divided by 1.1 is roughly 1.8 ohms.
Power = VI which works out to 2.2W for each resistor.
You could possibly get away with a single 5W 1 ohm resistor but you would be getting a slightly higher voltage drop and you would be pushing the limits of the resistor. A single 10W 1 ohm resistor should work as long as you're happy with the reduced voltage and current for the LEDs
