to light an LED with a 12V, what resistor value we need? « on: June 22, 2013, 09:26:41 am » What is the ideal value for the current limiting resistor connected in series with an LED in a circuit runs on 12v? And what value of a resistor we need to light the LED with the following voltages? 220V, 5V and 24V? Thanks in advance! Logged. h1386343. The main reason LEDs need resistors is to protect the LED from excessive current which can permanently damage the LED. LEDs have current ratings which indicate the optimal current at which the LED operates effectively. The new LEDs are simply ON/OFF and have 2 wires. Since LEDs do not draw as much power as the stock filament bulbs, load resistors (that come with the LEDs) are included. These resistors get very hot because they pass a lot of current so the electronics on the motorcycle will not think there is a burnt bulb. in video i want to show you how to use LED light with 12v DC using resistor, or how to connect led to 12v DC Solder one end of a second copper wire to the long lead of the red LED. The long lead is the cathode (positive) lead of the LED. Hold the negative side LED/copper wire to the negative terminal of a 1.5 to 3.0 volt battery. Hold the positive side LED/copper wire to the positive terminal of the battery. The red LED will light and will not burn out. 1YAQUcn.

do 12v leds need resistors