[JohnnyG]

Yeah, that's what I wasn't getting through my head - the embedded resistor is valued to meet the specs of the LED at 12V. Would still like to know the specs of the LED and resistor separately, but with what is known and using PWM there should be no issues.

 

[TomatoSoup]

Am I misreading this? From John's quote, this appears to have a "current limiter" not just a resistor (unless current limiter is just marketing speak for a resistor!)

If you've worked with LEDs much in the past you will be familiar that most LEDs that are around the 20mA range will only work on approximately 2-3v without a resistor, depending on the color and technical specifications. These LEDs are particularly special because they have a current limiter inside the actual lens itself. What makes these even more rare is that we have taken it a step further and designed them so they will work with voltages up to 15v. While we don't recommend running them continuously at 15v, they will be ok with occasional spikes. This is something you will definitely not find in other LEDs similar to these out there.

 

[JohnnyG]

What a resistor resists is current

 

[TomatoSoup]

What a resistor resists is current

sigh.

 

[JohnWR]

Am I misreading this? From John's quote, this appears to have a "current limiter" not just a resistor (unless current limiter is just marketing speak for a resistor!)

An interesting question, but after I found the specification I looked (briefly) into current limiters. I didn't find anything that it looked like could be built into and LED of that size. Also my (briefer) look into the operation of a small current limiter would not seem to me to behave like the description I quoted, since they mostly have the effect of interrupting flow when it is too high, pretty much using PWM. That would not seem to me to result in lower output at lower voltages, but would instead maintain rated output right down to the point where the voltage drop across the assembly equalled the supply voltage at which point it would shut off. Or maybe not.

In any case, the price would not be consistent (in my mind) with a device that was that sophisticated.

 

[TomatoSoup]

An interesting question, but after I found the specification I looked (briefly) into current limiters. I didn't find anything that it looked like could be built into and LED of that size.

Undoubtedly you are correct. But, as an aside, I have a number of different "12V" LED assemblies with const current drivers, and the circuitry is pretty small. See the attached web pic. In this case, the driver is just the 4 components on the right (plus an optional bridge rec on the left). Again though, if the LED under discussion is v.small (I haven't seen it) then even that wouldn't fit.

 

[JohnnyG]

A resistor is not a current limiting device?! Please explain.

2 second Google search what does a resistor do - Google Search

 

[JohnnyG]

what is a constant current driver - Google Search

 

[JohnWR]

A resistor is not a current limiting device?! Please explain.

2 second Google search what does a resistor do - Google Search

In a crude sort of way, yes it is, as it will limit the current to a specific value given an equally specific set of circuit parameters. The term "current limiting device" generally implies something that will limit current to a specific value regardless of the voltage applied or load present, as is noted in the link you quoted below.

what is a constant current driver - Google Search

A resistor cannot do this, so it is not a true "current limiting device".

 

[load97]

Is there a way to tell the cathode & anode side on the LEDs that are currently on there? Almost looks like there is a corner indented when looking at the one photo. Also, each LED had a gold dot (on circuit board) on one side. I know with the mirror LED upgrade the corner had the indent, and replaced the same way.

 

[JohnnyG]

In a crude sort of way, yes it is, as it will limit the current to a specific value given an equally specific set of circuit parameters. The term "current limiting device" generally implies something that will limit current to a specific value regardless of the voltage applied or load present, as is noted in the link you quoted below.

A resistor cannot do this, so it is not a true "current limiting device".

It's all word salad...very much context based. A "current limiting device" would typically be a fuse, circuit breaker, etc. A "constant current driver" delivers a constant current throughout a voltage range. Since a resistor reduces/restricts/limits/regulates current, calling it "current limiter" sounds fair enough to me. Pretty limited ambiguity, given the context.

 

[JohnnyG]

Is there a way to tell the cathode & anode side on the LEDs that are currently on there? Almost looks like there is a corner indented when looking at the one photo.

The notch should indicate the cathode. If I understand what you're referring to as "gold dot" correctly, it is a "via"...an electrical pathway to the other side of the circuit board (could be to another layer of the board, but I'm betting this isn't a multi-layer circuit board)

 

[load97]

The ones circled in red

 

[JohnnyG]

Wild guess is test pads. I would have to assume they are all on the same plane. Likely positive, but I can't to tell from the pics.

 

[load97]

@rjgramps Here’s white LED’s installed. Same eBay company you bought from. What sucks is the left is way too blue. Company says both are white though. Problem I think lies is that the ones on the left are so small I think it’s too hard to get a more accurate color rendering. Tried a few companies that had that size in stock and all appeared about the same. So working on a slightly bigger size LED for the left that matches the right side better. Not all variations of the GM steering wheel controls use the same size LEDs unfortunately. At least not on the one side of the wheel from what I have found with the 3 sets of controls I have.

 

[rjgramps]

It is unfortunate that the color of your LEDs are not the bright daylight as expected. Yours on the left side in the steering wheel surely look blue. Please confirm that you soldered in leaded LEDs in place of the SMDs.

For reference, here is a picture of my Chevy Cobalt bright lime LED illumination. This picture captured the color fairly well. The radio buttons are the exact same color as these buttons.

FWIW: I later bought daylight LEDs for my trunk. They were a strip of SMDs in sealed rubber strips. Like in your steering wheel, these daylight LEDs are blue compared to the rest of my LEDs. These pictures are true to color.

 

[load97]

I bought some 1/4” bolt leds as they are called. I’m going to put one on each rear quarter panel under rear speaker somewhere. Have them come on when the doors open etc. anyway, I was looking but gave up, for a small led that would have an eyelid (lack better term), on it so the light would shine down and outward. Never found anything. Maybe someone else ran across something like that? Otherwise the bolt led I’m sure will be fine. Just that when reaching in to grab bags etc it might become (very) slightly blinding if reaching in far enough to grab a bag. Plus I was trying to go for more factory look.