Would a resistor dim this light?

Would a resistor dim this light I have for my cb

 

Install a lower wattage bulb?

 

Well I want to keep this cause it's a super clean looking led and I can't change the bulbs or anything so I just thought I could put a resistor in the positive wire and it would dim it

 

Yes but LEDs have threshold voltages below which you will get no light at all - so you need to pick the resistor carefully.

A diffuser or filter covering the LED might be a simpler solution.

 

That's true, didn't think about that. I'll probably do a filter and a resistor if a resistor alone won't work. The aluminum casing around the light also gets extremely hot so I was thinking a resistor will be like killing two birds with one stone and also lower the temp

 

Get yourself a potentiometer. It is a variable resistor like a volume control. Use the middle Tab and either end to vary the resistance. You reach when you reach the brightness level that you want, remove the potentiometer and measure the resistance between the wires. Then you can get a resistor close to that value and wire it in.

 

It doesn't work that way. If you install a resistor then it will also get hot. A circuit has xx amount of power that power will be used in the circuit in this case it would be heat and light. Adding another resistance will only split up the heat between two objects ( the LED and the resistor ).

 

Sorry to disagree with you Jimmyh, but putting a resistor in series with a circuit (a lamp)will increase the total circuit resistance, thus lowering the current flowing thru it. Lower current means lower power consumed, thus lower heat. The basic formula is Power=Volts x Amps, where Amps=Volts/Resistance. The voltage drop across the lamp will be reduced resulting in lower light output. This usually does not work well for a led, as it requires a certain triggering voltage before it comes on at all. OP might look into a different led with less lumen output.

 

Forward voltage is around 1.7V or higher (i.e. typically depends on the color and type of LED as well) and around 15-20mA is a fairly safe amperage guess.

Anyways, regardless of what I just stated, you MUST take into consideration how much wattage the resistor can handle!!! If it is, say, a 1/4W resistor and you're pushing through it around 1W, that thing is gonna be HOT HOT HOT and will, most likely, BURN!!! The point is is that you need to take that into consideration as well!!! You can probably try the POT idea and MAY BE have the POT a 1k ohm? I would imagine since those are likely Super/High Bright LED's and running off of the vehicle voltage (i.e. 11.5-14.5 around that range... so start with roughly the middle voltage, approx. 13V). Also, see if you can put the DMM in-line and see how much current the light, as a whole, is drawing and then go from there. That's where "I" would start. Given that it is BLUE or what looks like it in the pic, who knows, my eyes are getting bad as I get older as it could be RED for all I know , I'm guessing around... possibly... 25-30mA of current draw??? Take measurements as far as current draw is what I would recommend doing first... and... again... go from there to figure what you would need to cut the brightness by half or so.

I hope this helps?

 

Since I am not sure, I’m just going to resist addressing this question!

I would have a tendency to agree though with nasaengr regarding current flow. That being said, I always question anything to do with electricity and look for the guy with heavy-framed glasses and a pocket protector.

 

I am well aware of Ohms Law. Thanks for contributing. The resistor is still going to get hot and the LED is also going to get hot. It may or may not work as not all LED's are able to be dimmed. Some do and some don't.

 

Years ago, I had a Mazda pickup that had an annoyingly bright high beam indicator. I cut a small circle of window tint and put it over it on the dash face. Problem solved.
That may not be doable here but something to consider.

 

ACTUALLY, pretty damn good idea there sir!!!

 

www.diodedynamics.com

 

I got a resistor from the local electronics store, it's a 560 something. I forgot what the guy said but he said it wouldn't get hot, so I tried it out and it worked like a charm. Better than I thought it would. I was also able to play around with how dim I wanted it with different resistors. But yeah anyways it worked out perfect

 

I like it. I find the high beam light in my truck highly annoying, especially since it won't dim with the other lights.

 

You are usually pretty safe with 1/4W and 1/2W resistors for most cases. It's the current going through or should I say being resisted and the voltage drop across that resistor, which in turn is what wattage it is dissipating. Hence, don't and/or try not to go beyond the 1/4W and/or 1/2W range of said resistor. There are even 1W resistors, but I rarely ever see those things as well as other possible wattage resistors I'm just not familiar with as I've never had to deal with them before?!

Anyways, it's not that hard to do as long as you just be within reason.

Glad it worked out for you for sure!!!