Carbon Film Resistors for LEDs: 150, 180, 390, 470 & 560 ohm - Customer Questions

Frequently Asked Questions by Oznium Customers

I am trying to hard wire a single white led light that's powered by 3 AAA Batteries to my vehicle. So I can do away with the Batteries. I have check with my meter and I am getting 4.5v to the led. So what resistor would I need to drop from my vehicle 12 v to 13 v to 4.5 v
If you enter these values to our LED Resistor Calculator:

Supply voltage: 14 volts
Voltage to LED: 4.5 volts
Desired LED current: 20 milliamps

You'll see we recommend a 560 Ohm resistor with a power rating of at least 1/2 W
This resistor with a tolerance of +/- 5% has the color code: Green, Blue, Brown, Gold

Our 560 Ohm resistors are in stock and ready to ship.
What size of resistors would I need to come up with .685 ohms.....they will be inline, replacing a chipped key - by Nick (cheney wash 99004)
Wen need more information to figure that like what type of led are using, voltage rating etc. Here is a link to a resistor calculator: https://www.oznium.com/led-resistor-calculator
do I need a resistor for my 12volt (not led) headlights on my 1940 Ford - by Jerry
Sorry, we don't have information on that.
I want to place several different lengths single color led flex arrays on a 12v motorcycle. I take it I would need a 12vdc led flex spool. Would a resistor be required to connect them where they are used as running lights only? I also intend to use some locations as both running and turn signal/brake lights. I know I have to install a resistor inline of the running light circuit coming in to reduce the power as a dimmer. I believe I should also install diodes so current can only flow one way. My biggest issue is figuring out what resistor to use, when needed. Any advise would be greatly appreciated.
Prewired leds do not require a resistor. You can use an inline fuse to protect the leds.

We have this strip in dual color for running and turn signals: https://www.oznium.com/flexible-led-strips/2nd-gen-side-emitting-led-strip
I have a led strip 24''with 24 LED'S for ambient lighting to illuminate my step on my truck when opening the door. it came with batteries which produce 4.5 volts and use 350 mA . I want to run in to my 12v system on my truck so I don't have to worry about batteries. what do I need to do this a resistor or something else that steps down the voltage ? - by ROBERT
Not a resistor but maybe a DC to DC converter.
do I need resistors to hook flex leds to 10 inch woofers - by Romnial (Kentwood, LA)
You should not hook LEDs directly to your subwoofers!
You should instead use a music interface.
All I know is the led strip is 12v. I have 3 led strips. The strips are 15/7/7 smd(s). What kind of resistor do I use?
Assuming you're powering them with 12v, you do not need resistors.
What voltage are you powering them with?
I'm trying to create an LED strip for an offroader that's a combo brake/ marker light. I'm looking to do a box of lights 12 LEDS across and 9 LEDs tall. (so each light has 42 LEDS). I was hoping to find something that would fit, but, am not finding anything that fits easily.. How many resistors would I need and in what configuration to be able to have the simplest wiring? (i.e. have each light with one wire for low power, one for high power, and one ground wire) Thanks. - by Douglas (7408 Belclare Ct, Je)
Rather than resistors, you should use one of our LED dimmers.
Have Mercedes sprinter. Want to use wireless LED tail light bar. Need adapter with resister to plug transmiter into.Anything available ? - by Ron (Calif.)
Sorry, no idea what resistor you'd need for that.
do you need to run a resistor for back-up led lights or only turn signals?
It depends on how you hook them up. Most likely yes, if you are doing individual LEDs. No, if you are using our strips; they have resistors already built in it.
I have a 99 corvette and I am following the install shown on your site. I think the resistors I have are not strong enough to pull the power down. My question is what size resistor should I use in my car? - by Charles (Charleston, SC)
If you have a moment, please check out our LED resistor calculator. You can simply plug in your numbers and it will tell you.
I have read that after a while, led strips burn out due to alternator spikes in the charging system. What do you use to prevent the led's destruction? - by Ken (Redding, Ca.)
A fuse.
Can resistors be cut or bent to fit into tight places? - by Sora (Augusta, GA)
They can be bent once or twice, but bending them over and over will make them snap apart.
do i need resistors to connect six 12v led bulbs in paralel i'am using a 12v power adapter, what zise resistor do i need? - by Lino
Depends on the LED/LEDs used. Your question is to broad to give a specific number answer.
I am trying to repair my Aftermarket LED Tail lights and 3 LEDs are currently out in a row for the brakes. My question is will I have to replace all 3 LEDs and the resistors? if I have to replace the resistors, would you happen to know if I would need to buy 2 resistors for them? - by Outphase (Santa Cruz, Cali)
We don't know since it is not our Tail Light kit.
what does a resistor do?
do you have to have them?
They're designed to lower voltage so you can use individual LEDs and related products that aren't suitable for 12-14v automotive applications by themselves. They are not required for all applications. Typically only loose, non-pre-wired LEDs will use resistors.
i would like to use these in commercial setting, how do i power down 110v to 12v? - by Rich (red hawk casino)
You'd need a power converter, not a resistor. See our 12v converters here: https://www.oznium.com/power-adapters
I plan to make a custom 3rd brake light for my car using roughly 40 3mm LED's. Does this mean i need 40 resistors? - by Jamie (Indianapolis,IN)
If you wire them in parallel, yes
If I were going to solder your led's directly into a sealed GM dash could you send me the resistor/led(unit) only?
Thanks in advance D. - by Denn (Toronto, Canada)
Please contact our Customer Support Team
I am planning on using 25 of the 5mm Green LED's. Which type of resistor should I use? do I need a resistor on each LED? - by Chad (Tofield, Canada)
I would recommend using a resistor on each LED. It will help your LED's last longer and glow to their full potential!
I want to run 10 superflux leds in a row. Do i have to power each with a separate power source, or can i use the resistor to put between all 10 for power, and use at the last one only one power wire. so it would be ( led resistor led resistor led ect...) - by John (North Brunswick, NJ)
It is possible to use a single resistor, but with superflux LEDs, it is generally more practical to use a resistor for each LED.
Can these be used to dim the flathead led strips? If so, which would be best to use to dim white flathead led strips? How much do they dim? - by Duke
These will not really work to dim the flathead led strips.
I'm working on some custom taillights and plan to use 4-6 superflux 4chip yellow LEDs in each taillight for turn signals. What I was wondering was do I need any resistors for them? I will be using a LED Flasher, and I didn't know if I needed the resistors for voltage or to put enough draw on them to allow them to not have the hyper-blink. Thanks - by Stephen (Fort Wayne, Indiana)
Whether or not you will need resistors depends on the voltage going to the LEDs and how many amps it can handle. To prevent the hyper blinking you use something called a load resistor, which Oznium currently doesn't supply.

Here's an LED calculator to help you figure out what resistor size you need, if you decide you do.
I plan on making some custom turn signals using the "Rigid 5mm LED Dome Light," which resistor or resistors will I need to used so my car won't think the turn signal is out because of the low power draw?
You would need a specialty resistor that Oznium does not currently supply. Our resistors only lower voltage. You need a load resistor.
I use a neon license frame light and I get lots of engine noise when I listen to the the AM radio. Any suggestions? If resistors are the answer, how are they wired?

Loel Stein
You have an electrical current too close to your antenna's wire. Resistors will not help.
Is there a way to dim these down to match some crummy 12v lights? I replaced the ones in my Climate Control on the dash of my Corvette and they look great but they outshine the radio now. Suggestions?
Thanks - by Dan (Yakima, WA)
Yes, you can double-up resistors to dim down LEDs.
If im running say about 20 Super Bright LEDs, how many resistors would i need? - by Eugene (NorCal)
I would use one resistor for each LED.
I am thinking of wiring these into my 1 watt leds I got from you all. Do i solder these on the possitive side? and should I use both positive terminals in the LED?
I am sealing everything in acrylic and using them in my wheel wells. - by Jason (Spokane Washington)
Yes, resistors are soldered onto the positive side. Yes, we recommend hooking up both positive terminals.
What resistors do we need for wiring 4 1-Watt star LEDs to the same power source in a car, assuming they are wired together daisy-chain style? - by Allen (SF, CA)
It would be much better to use an LED driver for that. If you used resistors they would be huge and very inefficient.
How many LEDs can be used for one resistor?
There is no simple answer. It depends on the size of the resistor, the voltage of the LEDs, your supply voltage, the number of LEDs you want to run in series, the current draw of the LEDs, and the power rating of the resistor. If this is too complicated for you, why not just use pre-wired LEDs that hook up directly to 12 volts?