[El_Doug]

I'm planning on back-lighting my volume knob, and while I am very familiar with wiring LEDs, I have no idea what would be an appropriate brightness level for the common 4-led setup. 
 
I'd like to avoid spending time experimenting (does that make me a bad diy-er?) - if anyone has successfully implemented this, I'd appreciate hearing what values you used  

 

[beerguy0]

Quote:

I'm planning on back-lighting my volume knob, and while I am very familiar with wiring LEDs, I have no idea what would be an appropriate brightness level for the common 4-led setup. 
 
I'd like to avoid spending time experimenting (does that make me a bad diy-er?) - if anyone has successfully implemented this, I'd appreciate hearing what values you used  

Put in a pot, and dial the brightness you like. I'd put in some minimum resistance to prevent roasting the LEDs withe the pot zeroed.
 

 

[wakibaki]

You want, say 2-20mA.
 
Say your supply is 12V.
 
A LED will drop 1.8 (red) to 3.6 volts (blue).
 
If you use a blue one, you have  12-3.6 = 8.4V left. (If you have 2 LEDs, you put them in series, 12-7.2 = 4.8)
 
You want 20mA at the brightest setting. That's 8.4 / 0.02 = 420R. Nearest E24 value is 430R.
 
You want 2mA at the dimmest. 8.4 / 0.002 = 4200R. 5000R is the nearest value pot.
 

 
So that's how you do those calculations. You can sub in a fixed resistor.
 
w