Not just any 330 Ω resistor will work for us, we need the resistor to meet or exceed the resulting power dissipation. Note: A resistor's power is rated in watts. The formula for electrical power is P (Watts) = I (Amperage) * V (Volts) 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. All the calculators in step 2 are just doing some simple math that you can do at home: The formula to calculate resistance in a circuit is: R=V/I or, more relevant to what we're doing: (Source Volts - LED Volts) / (Current / 1000) = Resistance * So if we have a 12v battery powering a 3.5V 25mA LED our formula becomes: (12 - 3.5) / (25 / 1000 Usually the replacement type LED bulbs (many LEDs per bulb unit) are designed to divide the 12 volts across each of them to achieve the correct voltage on each individual LED (~ 1.9-3.6 volts usually). The bulbs have a couple rows of 3 or 4 LEDs in series (12v / 4 = 3 volts) bunched together. 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. Vay Tiền Nhanh Chỉ Cần Cmnd.

do 12v leds need resistors