Bright LEDS

tmp3061Just for the sake of it I bought 10 LEDS from China from Ebay, not your normal run of the mill type but the new ultra-bright types they use on mains lighting. I think I paid about 20p each if that and had to wait a couple of weeks – but they are amazing.

As you can see in the photo they are meant for surface mounting but they’re not too small to simply wrap a thin wire around each end. Anyone with ANY soldering skills should be able to make use of these around the house – but the power requirements are a little more interesting than, say a filament light. Like all other LEDS these are current-driven, not voltage-driven so you have to be a little careful – never connect them to low-voltage power without a resistor or you will send them to their maker.

tmp7444The operating voltage is around 4v but the key thing is to ensure they get no more than maybe 250ma. I have a power supply with current limiting so I simply set the voltage to 6v with maximum limit of 250ma (which means the voltage will drop accordingly to ensure no more than 250ma). With 3 in series they’ll run off 12 volt with a simple resistor or preferably a current limit circuit.

The results – amazing – they do get slightly warm and I guess they should be mounted on a board with a little copper or aluminium underneath for constant operation but I can see lots of uses for these! The photo on the right really does say it all – blinding white light. At 4v, 250ma you’re looking at around 1 watt – which is exactly what they’re supposed to take – typical GU10 lights might use 3 of these – but I’m thinking SAD LIGHTING. Imagine what a row of 50 of there would look like in a row – certainly get you up in the morning for a mere 50w!

There is now widely available LED strip in a range of colours- it’s bright but not super bright – what would it be like to see a strip using these babies! The day of halogen car lights must surely be near it’s end?

There are of course no shortages of people trying to sell expensive supplies for this “new” lighting – which has in fact been around for over 40 years – just not so bright – but in fact there are simple ways to drive these – as usual, Instructables has something to say on the subject… http://www.instructables.com/id/Power-LED-s—simplest-light-with-constant-current/  though personally I think it would be cheaper to use 2 diodes (base to ground), a pull up resistor  of maybe 1k (base to +), a BC337 and a 3r emitter resistor (to ground)– but there you are…

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