On Tuesday, 8 July 2014 00:17:51 UTC+1, Theo Markettos wrote:
Johny B Good wrote:

The blue LED indicator lamps are the worse for this excessive

brightness issue. On older kit using different lamp colours, they seem

to have decided on the same value of current limiting resistor for all

three colours (red, green and blue) with the result that the blue is

uncomfortably bright compared to the more muted red and green lamps.



I've found that if I pick a resistor value that uses orange instead

of red as the third band on the originally fitted resistor, that seems

to drop the brightness to a more comparable level. :-)


I recently designed a PCB with a series of indicator LEDs for different
power rails, and decided to use a rainbow colour scheme
white/blue/green/yellow/orange/red
All but the white came from the same Kingbright range.

One problem is that our eyes have a differnt sensitivity to that of those devices that measure brightness. They can also have diffenrt angles of view which can be another annoyance.



Not only were they painfully bright, they were all different levels of
intensity. I had to spend half a day tweaking the resistor values to match
the intensity across the array.

You shouldn't use the voltage or current to change LEDs brightness you shoud use constant cuttent and PWM to adjust the intensity.

To make it more exciting, the power rails
were different voltages. Some of the resistor values went up by a factor of
100.



Theo