led lights.

Any of you electronics experts know if L.E.D.s give off any sound?
Most lights sources give off some, but I wonder if leds hum or buzz at all and if so how much?

No sound. They are a semiconductor, and very efficient (no real heat either).

One big trouble is getting decent white LEDs. They're not accurately calibrated, so LEDs (even from the same batch) can vary in colour temperature. Slightly niggling is their forward voltage of 4.2V is higher than regular LEDs (which are often around 1.2V). A normal red LED you could drive straight off a NiMH cell for ages.

I have a little collection of white LEDs in my drawer, waiting the time when I can sit down and sort out a supply option and mount them onto a lens for macro lighting...

Matt

Hi
The cheapest source I,ve found for whit LED's is;-

http://cgi.ebay.co.uk/10-JUMBO-WHITE-11000mcd-led-10mm-led-leds-leds_W0QQitemZ74...

He sells 3mm, 5mm and 10mm LED's very cheaply, if you contact him before he despatches them and tell him your battery Voltage he will 'throw in' the resistors as well! (if he has them in stock).

I've tried 10X5mm ones for Macro work with mixed results, the colour balance was fine but I think you need about 20 to get a reasonable light level.

Chris