ezland00

I brought the switchback led bulbs, but i am not what is the correct size of resistor i need. i saw couple threads that people use 2 6ohms 50w per led and others use 4ohm 100w.

Does anyone know the math to calculate the correct resistor.

Q's
1. does all power resistor heat up like a bulb?
2. i have some 10ohm 50w resistor will this work.

thank you all

Tripnbeats

all resistors heat up it means they are working.... BUT they are not supposed to heat up the way some people describe with turn signals. so obviously they arent using the right ones but they'll work.... i wont do them until i get back to my shop and probe the lines to see what resistance values the lines have

6spMike

I don't know about the specifics of LEDs, but this sounds like simple circuits stuff.
You need to know what voltage the LEDs are supposed to be supplied with, and how many amps they draw at that voltage.
Then use ohms=volts/amps to determine the ohm value of the resistor you need to drop the 'extra' voltage.
Once you know how many ohms the resistor you need is and how may amps will be flowing through it, use watts = amps^2 * ohms to determine how many watts will be dissipated. Buy a resistor rated at 2-3x the number watts you will dissipate.

Example (I've got no clue if these values are even close): led is 5 volt and draws 1 amp.
12 - 5 = 7 volts to drop.
1 amp flows through the resistor, since you hook it in series.
7 volts / 1 amp = 7 ohms.
1 amp^2 * 7 ohms = 7 watts.

So in this example you'd need a 7 ohm 25 watt resistor.

I hope this helps.

xtremmeballer

http://led.linear1.org/1led.wiz


^ i used that to put leds my ps3.

Srry if its of no use to u.

frenchnew

The resistor is to correct the faster flash rate because the LED does not draw enough current. The flasher circuit of the TL has a load detection circuit to detect burned out bulb. When the circuit draw less current then usual the circuit will trigger the faster flash rate to indicate the burned bulb condition.

It is use across the LED's 2 wires (One Common and the Flasher Led) so that the current consumption is about the equivalent of a regular bulb on the flasher circuit.

see the following thread for more information:

https://acurazine.com/forums/showthr...hlight=flaSHER