LEDs different current/voltage

Hello,

From what I've read in the many basic tutorials on LEDs, you can wire
different color LEDs in series on a single resistor, regardless of their
individual voltage, if the current requirements are the same.

I have a single 100 Ohm resistor in line with a 3.2V, a 3.4V and a 3.5V LED
in series on a 12V source that works great. These LEDs are all rated at
30mA, with an operating current of 20mA.

I also have a 1.9V red LED, rated at 50mA, with an operating current of
20mA. Adding this LED to the other three brings the voltage drop to 12V.
Can I simply omit the resistor or is a minimal one needed to limit the
current to 20mA? It has the same operating current as the others, but is
rated for a higher max, does this matter?

Does the order of the voltage drops matter to the current flow?

Thanks in advance for any advice before I fry a few components in
experimentation.

Scott in Dunedin





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