I understand the problems with connecting LEDs in parallel as has been pointed out in many threads on this forum. But practice seems to indicate that it is not as catastrophic as it seems. I found 15 red LEDs in my parts box. One measured a forward voltage of 1.87. The highest of the 15 measured 1.91. All the rest were between 1.88 and 1.90. I was surprised to see this uniformity. I paralleled the lowest, the highest, and 8 of the ones in between. I put the paralleled LEDs in series with a fully charged LiPo and 20 ohms of resistance. They are all visually identical. So I added a yellow one with a forward voltage of 1.97--it is a little dim, but bright enough to be used as an indicator.
Now, I wouldn't try to sell a circuit which violated the rules like this--actually, I wouldn't try to sell any circuit. But to tell someone who wants to make a simple project using small LEDs that it should not be done, that the LEDs will self destruct, seems to me like bad advice.
Now, I wouldn't try to sell a circuit which violated the rules like this--actually, I wouldn't try to sell any circuit. But to tell someone who wants to make a simple project using small LEDs that it should not be done, that the LEDs will self destruct, seems to me like bad advice.