What size resistor? - Toyota Yaris Forums

drell42 · 06-03-2006, 04:39 PM

Okay I have a 2.5v LED that I need to hook up, but i need to know what size resistor to use, ive google ive asked im confused.... PLEASE HELP!

Thanks, Rick!

Leenis24 · 06-03-2006, 05:52 PM

use this to find out
http://ourworld.compuserve.com/homep...Bowden/led.htm

v = volts mA = milliampere(Milliampere, an SI unit of electric current, worth 0.001 Amp) Ohm = electrical resistance or electrical impedance

with 1 led, at 2.5v, a 15 mA current, and a 14.2v source(the alternator will push 14.2 volts), it says a 750 Ohm. I would use a resistor higher than that number. I personaly would just use a 1k (1000 Ohm) resistor that way your safe.

johnnyfive · 06-04-2006, 02:25 AM

check this out http://led.linear1.org/led.wiz

very handy little helper when it comes to wiring LED's

it will give values for resistors, and pratical array patterns if you are wiring multiple LED's it will even help you with resitor color codes, and give you a wire diagram for the layout :)

Leenis24 · 06-04-2006, 08:02 AM

hey johnnyfive, that site is really cool, i bookmarked it.

SophieSleeps · 06-04-2006, 10:30 AM

Quote:

Originally Posted by drell42

Okay I have a 2.5v LED that I need to hook up, but i need to know what size resistor to use, ive google ive asked im confused.... PLEASE HELP!

Thanks, Rick!

You'll need to know the operating current of the LED before you can determine the resistor needed.

A 1/4 watt resistor is plenty. If you go up in wattage it won't do anything...so if you can only find 1/2 watt it won't make a difference.

If you are putting multiple LED's in...I suggest wiring them up in series (connect the + of one LED to the - on another and create a chain) because it seems easier than running them in parallel.

What is your project? Pics? LED's rock

drell42 · 06-04-2006, 04:53 PM

Quote:

Originally Posted by Leenis24

use this to find out
http://ourworld.compuserve.com/homep...Bowden/led.htm

v = volts mA = milliampere(Milliampere, an SI unit of electric current, worth 0.001 Amp) Ohm = electrical resistance or electrical impedance

with 1 led, at 2.5v, a 15 mA current, and a 14.2v source(the alternator will push 14.2 volts), it says a 750 Ohm. I would use a resistor higher than that number. I personaly would just use a 1k (1000 Ohm) resistor that way your safe.

Thats what i thought so I tried it again i guess that the first one that I had was defective. the LED is so that I know that the neon is on because I dont want to use the fugly switch that came with them!

pennystocks · 06-07-2006, 01:33 AM

So you use hot glue to hold em in place? I was thinkin of tryin somehting like this. Bought some LED bulbs, they suck, not bright at all.

also, how many do you think it would take to look nice and bright? and take it the wider the angel the better?

I was lookin at some of the 5 mm leds @ http://www.superbrightleds.com/leds.htm

SophieSleeps · 06-07-2006, 01:42 AM

Quote:

Originally Posted by pennystocks

So you use hot glue to hold em in place? I was thinkin of tryin somehting like this. Bought some LED bulbs, they suck, not bright at all.

also, how many do you think it would take to look nice and bright? and take it the wider the angel the better?

I was lookin at some of the 5 mm leds @ http://www.superbrightleds.com/leds.htm

I don't use hot glue to hold them in place. Hot glue prevents the leads from moving and shorting out.

I use superbrightleds.com LED's in 5mm.

pennystocks · 06-07-2006, 03:13 PM

So how do you get em to stay in place?

SophieSleeps · 06-07-2006, 07:14 PM

Depending on the surface, you can buy LED surface mount holders.
Do a radio shack search or something.

06-03-2006, 04:39 PM	#1
drell42 Drives: Blank Join Date: Feb 2006 Location: Not here Posts: 74	What size resistor? Okay I have a 2.5v LED that I need to hook up, but i need to know what size resistor to use, ive google ive asked im confused.... PLEASE HELP! Thanks, Rick!

06-03-2006, 05:52 PM	#2
Leenis24 lil' town up north Drives: 07 Yaris LB 5 speed Meteorite Join Date: Apr 2006 Location: Northern Vermont Posts: 92	use this to find out http://ourworld.compuserve.com/homep...Bowden/led.htm v = volts mA = milliampere(Milliampere, an SI unit of electric current, worth 0.001 Amp) Ohm = electrical resistance or electrical impedance with 1 led, at 2.5v, a 15 mA current, and a 14.2v source(the alternator will push 14.2 volts), it says a 750 Ohm. I would use a resistor higher than that number. I personaly would just use a 1k (1000 Ohm) resistor that way your safe. Last edited by Leenis24; 06-03-2006 at 06:32 PM.

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06-04-2006, 02:25 AM	#3
johnnyfive Drives: 2007 Yaris S Join Date: May 2006 Location: Milwaukee WI Posts: 582	check this out http://led.linear1.org/led.wiz very handy little helper when it comes to wiring LED's it will give values for resistors, and pratical array patterns if you are wiring multiple LED's it will even help you with resitor color codes, and give you a wire diagram for the layout :)

06-04-2006, 08:02 AM	#4
Leenis24 lil' town up north Drives: 07 Yaris LB 5 speed Meteorite Join Date: Apr 2006 Location: Northern Vermont Posts: 92	hey johnnyfive, that site is really cool, i bookmarked it.

06-07-2006, 01:33 AM	#7
pennystocks View User's Garage Drives: 07 Civic Si Coupe(Black Pearl) Join Date: May 2006 Location: Chicago, IL Posts: 159	So you use hot glue to hold em in place? I was thinkin of tryin somehting like this. Bought some LED bulbs, they suck, not bright at all. also, how many do you think it would take to look nice and bright? and take it the wider the angel the better? I was lookin at some of the 5 mm leds @ http://www.superbrightleds.com/leds.htm

06-07-2006, 03:13 PM	#9
pennystocks View User's Garage Drives: 07 Civic Si Coupe(Black Pearl) Join Date: May 2006 Location: Chicago, IL Posts: 159	So how do you get em to stay in place?

06-07-2006, 07:14 PM	#10
SophieSleeps Podiatrist Drives: Turbo IS300 Join Date: May 2006 Location: MA Posts: 83	Depending on the surface, you can buy LED surface mount holders. Do a radio shack search or something.