On Fri, 18 Apr 2014 12:50:36 +0100, Daniel wrote:

On 18/04/14 00:32, Uncle Peter wrote:
I just got some solar garden lights, and they seem to power an LED
(colour changing) from a single 1.2V NiMH. Can you get LEDs with a
forward voltage that low, or does it have a booster in it? All I can
see is a microchip (one of those black blobs so I don't know what's in
it), a capacitor, and a resistor.

LED's are Light Emitting Diodes, so can work from about 0.6V .... or
even lower maybe!

I should have tested it before asking. The LED gets 2.4V. The battery is 1.2V, there must be a voltage doubler in the chip.

Also what surprised me is the tri-colour LED (which gradually changes through all the colours of the rainbow) has only two legs - the colour changing is controlled by a chip inside the 5mm LED - the input to the LED is a constant 2.4V.

--
A man goes into a library and asks for a book on suicide.
The librarian says, "**** off, you won't bring it back!"