What Resistor for LED light?

[Swampy]

I have a package waiting at the house. I purchased a new 3PDT switch from Pedal Parts to make my VOX wah true bypass. I also ordered a 3mm LED light and the grommet, but not a resistor. Radio Shack is on my way home but I don't know what to get. Anything else I'm missing? How about a little extra wire? How much and what gauge? Thanks.

I do need a resistor, right? Just getting into the pedal modding thing, so kinda noobish questions I'm sure.

 

[GuitarStv]

Re: What Resistor for LED light?

I usually use a 2.2k resistor. I mean, technically you should read the datasheet and recalculate the value of the resistor based on readings from your LEDs . . . but 2.2k usually works for me. Any small gauge (20, 22 or 24) wire will work fine, I like 22 gauge solid wire myself (don't need to worry about tinning) but some say that stranded is easier to work with. You probably won't need much if you're just doing a mod on a single pedal, but it's always useful to have some wire kicking around when you want to rewire a guitar, build some pedals, mod some pedals . . .

FWIW I've had great luck using this method of true bypass in pedal builds:

 

[Rich_S]

Re: What Resistor for LED light?

R = (9 - Vf) / Imax

where Vf is the forward voltage of the LED and I is the current you want. It should be less than the max forward current of the LED, somewhere between 50 and 75% of max. More current makes it brighter and uses up batteries faster.

 

[Swampy]

Re: What Resistor for LED light?

Thanks guitarstv! Ill do the 2.2k. And I agree on the having extra wire on hand.

Thanks again.

 

[Swampy]

Re: What Resistor for LED light?

R = (9 - Vf) / Imax

where Vf is the forward voltage of the LED and I is the current you want. It should be less than the max forward current of the LED, somewhere between 50 and 75% of max. More current makes it brighter and uses up batteries faster.

= Greek to me. Rich, not trying to be a smartazz, and I so appreciate the response. As I do more mods and start pedal builds I really need to learn more on this stuff. Again thanks for the help.

 

[Swampy]

Re: What Resistor for LED light?

I did re-read that. And I does seem to make a little more sense to me. 8)

Thanks again.

 

[trevorus]

Re: What Resistor for LED light?

= Greek to me. Rich, not trying to be a smartazz, and I so appreciate the response. As I do more mods and start pedal builds I really need to learn more on this stuff. Again thanks for the help.

If you're looking to mod stuff, it's time to learn ohms law, among other things. Knowledge is power! Actually, power is watts, and watts = volts x amps

 

[GuitarStv]

Re: What Resistor for LED light?

My issue with calculating a specific value to use is most of the LEDs I've got are at the bottom of a big drawer and thus I don't have a specific model number that I can get exact datasheets for.

 

[Swampy]

Re: What Resistor for LED light?

This is the specs on the LED...


LED T-1 3/4 3mm clear lens green in color, 5000mcd Forward Voltage (V) : 3.2 ~ 3.8 Reverse Current (uA) : <=30

 

[Swampy]

Re: What Resistor for LED light?

Based on that, a 2.5K should be ok....50%. Or am I way off?

 

[Swampy]

Re: What Resistor for LED light?

Picked up a pack of 3.3k, and also some 2.2k's. I'll go with the 3.3k's as that is a little over 60% of the vf. I'M LEARNIN'! LOL

Now if I can just find time to do this tonight, as I also need to work on a headstock.