dimming 2 leds in series with a pot..

[deadastronaut]

ok this should be simple right? ..perhaps not!..

i want 2 hi bright green leds in series to be controlled with a pot to go from very dim to bright, but using the full range of a pot...not just the last quarter of the pot...

ive tried various pot/resistor combinations and it just wont have the full dim to bright 'gradually'....any ideas.?

this is how i have it so far

9v >lfo  > led> led >pot> resistor >ground....its for a depth control...(this is coming out of an lfo).

my voltages from the leds to ground swing from 1.4v when my lfo is slow..and 0.72 when lfo is fast....

my voltages going into the leds from the lfo are 4.9 when lfo is fast..and swings from 2.3 to 6.7v when slow..these readings are with a 1k resistor from the leds to ground..

so what pot and resistor combination would you recommend for that 'gradual' led fade for when its slow and fast?.....hmmm...thanks..

[jonny]

Yeah this is probably more difficult than it seems. But what I'd do is put a pot say 100k in there first to find how many kohms you need to turn off the LED. Then find the closest pot that matches and try lin/log/anti-log to see which works best? For a depth on a trem i designed I just biased my lfo, not as good but I wasn't after a normal depth control.

[deadastronaut]

cheers johnny,

yeah i thought this would be really simple..but its kicking my butt...like all simple stuff usually does ironically..

[deadastronaut]

right ive got it using that method...sort of.

my best reading was 19.2...with a 1k...

so i stuck a 22k pot..nearest i had...with the 1k...its ok.much better range over the pot,.but it doesnt dim fully....hmmm...