On 07/07/2014 08:17, Dave Liquorice wrote:
On Sun, 06 Jul 2014 18:33:10 +0100, alan wrote:

I toned down a blue LED by inking over with a red pen

Why do makers have thse indicator LEDS so bright? On the little (two
thumb size) wireless keyboard they are so bright it makes it hard to
see the keys. Bought a NAS enclosure LED on that lit the room up at
night, attacked it with snips and aditional series resistor. Don't
know what value I ended up at but the current was 50 uA (micro amps)
and it was still a bit bright. The thing would glow dimly if you just
lighly touched the wires with dry fingers.

The LED makers have vastly improved the efficiency of LEDs with time but
electronic engineers still give them about 10mA drive current!

I have a cute little demo circuit with an original 1970's era red and
yellow LEDs in series with modern ones and the result is startling.

--
Regards,
Martin Brown