Before I go on, I should stress that I have read many many other forums and scoured all stackexchange recommended 'questions that may already have your answer' things, and none of them answer my question.
Let's say I decide to put 3x 20mA 3v LEDs in parallel.
That equates to a power consumption of 60mA @ 3v = 180mW
But not all LEDs are created equal, and alas, one of the LEDs want 40mA. That should then increase the power consumption to 40+20+20=80mA @ 3v = 240mW and it burns itself out. Let's assume the other 2 LEDs are properly manufactured and draw 20mA
Shouldn't the other 2 LEDs still draw 40mA @ 3v?. It's not like I have a constant current device that forces 60mA.
Here is the scenario everybody talks about:
The power supply is 3v at 60mA (CC/CV)
- One of the LEDs is faulty and draws 40mA. The other 2 draw 10mA each (Since there is 20mA left over. Let's assume they split the current evenly)
- The faulty LED burns itself out. That leaves 60mA for 2 LEDs. So each of the proper LEDs use 30mA. But oh no!, one of them overheats and dies!
- The sole last LED is forced to use all 60mA of the current, and it soon overheats and dies.
3v power supply directly from a battery. There is no current limiting, current control, or anything at all. No resistor.
- Again, the faulty LED draws 40mA and dies.
- Shouldn't the other two LEDs still draw 20mA each? This means that overall total consumption of the circuit is only 40mA @ 3v.
- Boohoo, one LED breaks. That should be all. Why not?
My questions are:
Why would the two LEDs have to use 30mA if one dies? Why would the two LEDs draw the current meant for 3?
My 5 torches I have all have their LEDs arrayed in parallel. THey are high quality torches, most from Arlec. One of the torches have 16 LEDs in parallel. They do not have any resistor or anything. THe LEDs are literally all slapped onto a cheapo PCB, directly connected to the batteries. These torches all run fine, don't have varying levels of brightness, and haven't died on me in years. Why can't I do the same?