Slow flashing bright LED

I'm looking for a self contained slow flashing bright 5mm LED. 50% duty cycle ones are common, but I'd like something like one flash per 10 - or more - seconds, to cut down power consumption. No space in the housing to add electronics, so it has to be an all in one. 12 volts, obviously.

Reply to
Dave Plowman (News)
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Obviously?

Diodes dont come in volts!

They are valves if you prefer. You need a resistor in line or they are just a short. Different voltages need different resistors.

Reply to
Burgermans other computer

Granny, here's this egg. Now breathe out, and...

You can get LEDs with the appropriate resistor built in for 12v use. And obviously Dave isn't talking about plain LEDs, since he's asking for one with a flashing circuit built in - you don't think a simple diode will flash on its own, do you?

cheers, clive

Reply to
Clive George

Nope I have some here. They are nasty cheap ones but still flash, but no resister built in, you would need a 1k or thereabout.

You mean he wants a whole circuit built in! They make those? Cant see them in RS catalogue cd.

Reply to
Burgermans other computer

228-6032 228-6060 228-6076

et al.

Reply to
Tim S Kemp

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Unfortunately only with a 50% duty cycle, which is not what Dave wants.

cheers, clive

Reply to
Clive George

Not to you since you're a prick.

Sigh. I'm *perfectly* aware of basic LEDs being current driven.

However, there are flashing types that look just the same but have an internal IC - and these don't need a current limiting resistor for a wide range of volts.

I don't.

In both directions? Some valve.

The voltage is only one thing. You calculate the resistor value according to the forward current needed to drive it to the brightness you need (within limits) and the forward voltage drop.

The formula is Rs=(Vs-Vf)If

Reply to
Dave Plowman (News)

Dave has forgotten more than you'll ever know about electronics.

(c:

Douglas

Reply to
Douglas Payne

Cool! Things move on! LEDs will come with a car attached one day!

Reply to
Burgerman

That would not be difficult. (since anything without pistons cannot work in my view.)

Reply to
Burgerman

In some parts of Essex, they do...

Reply to
Tim S Kemp

I dunno if it's exactly what you want, but you could try an LM3909

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It's a very efficient LED driver. I put one in a simple toy for a nephew, driven by a single D-cell - that was over 3 years ago and it's still flashing away - on the same cell! It's essentially constant-current drain (~0.1 - 0.5mA) when running, so you can get away with a resistor & zener for supply.

Reply to
Albert T Cone

ROFLMAO.

Reply to
Conor

They have made these since I was 10-11 years old! I used them in a project I made thats what umm nearly 14 years ago!

Ed

Reply to
Ed

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