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When we use LEDs in circuits we always use a series resistor. We've made it even easier for you to calculate the value of this resistor with our LED calculator below. You can also watch this video where Kevin explains why we always use a series resistor, and explains how to calculate the value of the resistor.
Kitronik's suggested additional learning
LED brightness is controlled using a current limit resistor to drop some of the battery voltage, calculate the resistance using the formulas in this guide. A worked example shows the calculation used to work out the resistance to accompany an LED in a typical circuit using a 9V battery.
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8 comments
Mark Donnison
Hi Jerrard, it's always best to go with the manufacturer's guidance. If it says it requires a 3V supply, it is best to use a 3V supply.
Jerrard
Hi i got a 3volt 1w led torch globe.. If i connect it to a 6volt battery… Will it burn out….
SURINDER MEHTA
Use 20 ea Diode Red LEDs approx 2v each, I want to make parallel design which running on 12v battery for my bike indicators. Pls suggest Resistance value.. Pls help
SURINDER MEHTA
20 ea Diode Red LEDs approx 2v each, I want to make parallel design which running on 12v battery for my bike indicators. Pls suggest Resistance value..
Mark Donnison
Without knowing the specifications of the LEDs it is impossible to say.
SURINDER MEHTA
Hi want to make parallel red led (20 LEDs) design which running on 12v bike battery. Pls suggest me exact resistor value and help to make correct circuit. Thank you
Rob Haywood
Hi Ray, A single resistor for the amount of LEDs you entered in the calculator. Rob
Ray Taylor
H, ref. resistor calculator, is it giving me the resistor per led or single resistor for how many leds in the circuit