Are there any schematics for the internal components of an LED strip?
It's all shielded tightly and painted, so I can't figure it out just by looking at it.
I am illuminating a plexiglass cone with an RGB LED strip. I've put together in parallel 5 strips on a thin plexiglass cylinder in central axis of the cone, but it leaves a dark spot at the top, which I am trying to fill with an additional led. Initially I tried with a common individual RGB LED, but its colors doesn't really match the colors of the strip (the primary colors are ok, but combinations of them produce different grades).
As you may know, a LED strip will work with minimum 3 LEDs, but as this doesn't really fit at the top of the cone without touching the plexiglass or snapping the strip, I took a section apart and I am trying to re-wire it in a more compact way. I manged to do so, but again combining the color channels produce a different color from the main section.
Within each 5cm section. there are 3 LEDs and 3 resistor. Two 181ohm and one 391ohm. I read in some pages, that red LEDs needs lower voltage, so I assumed it goes with the 391ohm resistor.
I connected the LEDs in serial, with the resistors at the end of their - side, before connecting each channel to the main strip. The 3 pins on the other side are connected all together, leading to the + of the main strip.
Do you think the big resistor needs to go to another channel, or should I maybe connect the LEDs in parallel?
It's a bit of pain to solder these tiny bits to try out all the different combinations.
What LED are you using for the additional one? LEDs often have slight colour variations between batches and manufacturers so I would suggest taking one out of your strip to get a good match.
Connect them as Zapro said. Remember each "LED" soldered to the strip actually contains a red, green and blue LED and you are varying the brightness of each to achieve the intermediate colours. You will need to change the resistor values so the current through each of the red, green and blue LEDs is the same as the strip.
Take the strip of 3x LEDs and measure the current of each of the red, green and blue LEDs. Say the red measures 20mA (which is typical for small LEDs). The resistor needs to be R=V/I = (supply voltage - LED voltage) / Current = (12V - 2.2V) / 0.02A = 490 ohms. Repeat this for the green and blue resistors. The LED voltages in your link should be good enough for this calculation. If necessary you can increase the resistances a little of the colours are still off.
The resistors don't have to be placed near the LED. You could have four wires leading up to the LED and put the resistors at the base of the cone.
yeah that's a schematic for 3 individual LEDS, where each section of an RGB LED strip, contains 3 triple LEDS. I am not entirely certain whether the LEDs needs to be wired in parallel or serial. I guess I should do some measurements and compare against an intact section.
I think what you say about damaged LED due to heat may be a possibility. It took me some time to solder these tiny bits... and maybe one of them is indeed damaged.
chopsuwe:
What LED are you using for the additional one? LEDs often have slight colour variations between batches and manufacturers so I would suggest taking one out of your strip to get a good match.
You are right, each batch is slightly different and an previous strip I got, has even different resistors. The one I am using though, is taken from the same batch.
