Please explain meaning of this Photoresistor description

[arma61]

Hi lads

could you plse explain me the meaning of this description

- Photoresistor 6-18k ON, 100k OFF -

is this suitable, adding an LED in front, for subs the 100k pot of the Colorsound Inductorless Wah ? ( the pot is going from 100k to 0k pushing the pedal down)

and how does it works, I mean what do I get with light and what do I get without light.

I have to order this part but my clue about this component is zero.

Also I've heard and see about optocoupler (like VACTEC) but then again I don't know which one is suitable for the above.

I've also searched in this forum, but it's hard for me to get the whole thing clear so may be somebody could point me to what I need to buy (pref. from Banzaieffects).

thx 4 help
Armando

[GibsonGM]

Hi Armando,

I'm not an expert, but I'm not sure that LDR has the correct range for your needs.  I haven't built the colorsound, only tremolo and Easyvibe.   If the colorsound needs a range from 0 to 100K, it might be fine.

Anyway, that LDR you have says 6-18K ON, which means when light is fully shining on it, it has that resistance range.   Off is just the resistance when it is not in light, 100K.  Varying levels of light will cause varying levels of resistance in the LDR, which is how the circuit works. 

Check out for the specs required for the Colorsound. You might have to adjust the LED to get it to work (I'm sure there's something provided for that in the circuit?).

~Mike   

[arma61]

thanks Mike,

the "sweep" pot is 100K, and measuring it with the DMM I got that with the pedal in the "rest" position it is at 90K and with the pedal down I got almost 0; so comparing the 2 systems I should have  "dark LED" for the "rest" position and "full-light LED" for the "pedal down", isn't it?

The problem could be to bring that 6-18k close to 0!.

Thx
Armando

[Paul Perry (Frostwave)]

See how the wah sounds when you rock it over a limited range (that is, 18K to 90K instead of the usual range).
It's going to be a smaller range, but maybe this isn't a problem for you when you are playing, I don't know.