Problems adding an LED to an EH Pedal

[exacerbatus]

Hi,

I am trying to add an LED to a Octave Multiplexer that's already equipped with a 3pdt switch. I am able to get it to light constantly but not switch on and off. I've connected the cathode to a ground and have tried to connect the anode to multiple spots through trial and error with no luck. I also have a 330 ohm resistor on the cathode leg. I've included some photos of the layout.

Thanks for any help.

[Sock Puppet]

Hi,

The anode would connect to the middle terminal on the unused left hand side of the 3 way switch with either the terminal above it or below it (depending upon switch orientation) connected to battery positive.

Note that the input jack also switches battery negative, so the "ground" you've chosen could leave the LED permanently on when the jack plug is removed - you need to connect that side of the LED to (looks like) where the black lead leaves the socket going to the main board.

Hope that helps some,

Cheers,

S.

[exacerbatus]

Thanks for the reply.

Do I need the resistor? The LED has a steady current of 30 mA.

Thanks,
Ken

[Sock Puppet]

Yes you'll need a resistor - that current could be a tad high.

If you wanted 10ma throught the LED (depends on the LED) then:

(Supply voltage (9V?) - Volt drop across LED (say 2.5V))/.01A = 650R

Or preferred value 680 ohms. Your LED might not last long with the 30ma - again depending upon the LED.

Cheers,

S.

[Mark Hammer]

If you have any intention or need to run the pedal off a battery, you'll want to use a superbright LED so that it will be capable of yielding enough light but with much less current draw. If you score yourself something that's rated at 3000mcd or higher, you'll be able to get the same brightness you're accustomed to with as much as 10k or more limiting the current to the LED.