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How to Power These LEDs?

Suffolk Tony

Aim low, achieve your goals, avoid disappointment.
Hi folks, I'm fitting a digital amp into an old Denon case. This has an LED “Strip” arrangement, four LEDs in two strips as per the photo. I'd like to use this to show when the amp's powered up, but I've no idea how to work out the required power. The amp's got a 24v unregulated output which I'd like to use. Any help would be appreciated!

Xtr3YHW.jpg
 
We can figure out the circuit from the other side. That pcb already has a series dropper resistor of what looks like 510R.
You want to run the strip at only 1 or 2 mA unless you want to light your room with it.
Worst case all leds are in series means a drop of 8x1.5V so the resistor drops 12V.
You want about 10k for 1.2mA
 
Thanks for the comments & help chaps. The Denon's an old AV half-width UPO-250 amp. The LEDs are connected in series, with no additional components on the backside of the board. Yes, the resistor's 510 ohms. Not sure why there are three connections though.

MenjtFs.jpg
 
4 LEDs in series, say about 8V drop. That leaves about 16V which, across 10k is 1.6mA. You could go as high as 33k for 0.5mA, depends how bright you want it.
 
Many thanks, Mr Palfreyman. I'm not after anything bright, just enough to show the amp's powered up. I'll give the 33K a try.
 


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