Stupid LED Question...

[bt2513]

I have my LED hooked up to my 3PDT switch in my Neovibe.  No matter which way I orient the LED, I can't get it to light.  I'm running 18v to it which may be too much...  The switch is working and I've tested the voltage.  Also, I've tried two LEDs and no dice.  What gives?

[frequencycentral]

Are you using a series resistor?

Is the LED rated for 18 volts?

[bt2513]

No idea... ordered from Smallbear and they don't specify.

[frequencycentral]

Use a small value resistor (4K7) in series with the LED. Connect the resistor to + volts, the LED anode on the resistor, the LED cathode to ground - via the 3PDT.

http://www.beavisaudio.com/techpages/StompboxWiring/

[GibsonGM]

While you're in there, use a different LED with the resistor; if you ran it without a series resistor, it probably flashed for an instant, then destroyed itself! 

[Mark Hammer]

I know LEDs get touted as "not burning out", but that is with reference to the way in which an incandescent bulb can burn out if the filament is jiggled while the bulb is lit.  LEDs can burn out if the current passing through them is too high....and it can happen in the blink of an eye, fast enough that you may be momentarily looking in the wrong direction and the flareout happens during that 300msec when you weren't looking.

So, before you drive yourself nuts, verify the LED is functional.  I usually keep a couple of "dead-ish" 9v batteries around specifically for the purpose of a quick functionality check on LEDs.  If the battery juuuuuuuuuust barely tickles your tongue, it's a good candidate for this role.

[andrew_k]

bt2513: Run your status LED from the spare 'O' pad next to the power regulator. If you're running it at 18v I'm assuming you're connecting it directly to the power socket? The Neovibe can take various power sources, including AC. The regulator, however, will always put out +15v DC, so you have a consistent power source for your status LED.