flashing crazy led

Maniac_Man · Post by **Maniac_Man** » Wed Nov 09, 2005 1:12 pm

my white leds are stupid. im supplying the normal correct amount of volatge for them and one of them is flashing. also when it flashes the sound is affected. so when it goes on the sound goes kshzch! then it goes off and the sound goes pfft. does anyone know why?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Wed Nov 09, 2005 2:14 pm

yeah sometimes my white leds fluctuate a little too i think if you put a cap on it it would help but im not really sure were to put it

superdeformed · Post by **superdeformed** » Wed Nov 09, 2005 2:15 pm

What are you powering them off of? You may be putting too much of a load on whatever the supply is. Try replacing the LED, and if it still does it remove it and see if everything works then.

Post by **Gamelver** » Wed Nov 09, 2005 2:25 pm

oh, and if you want to put a cap, then get a 220-500ish uF electrolytic cap and wire the postive input to the input of the LEDs, and the negative side to ground. btw, do you have the leds wired in series or in parallel?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Wed Nov 09, 2005 2:27 pm

i use parralel is that better

Post by **Gamelver** » Wed Nov 09, 2005 2:31 pm

I personally think it is...never tried series, but theoretically it should be the same...just changes..er...something

....to figure out what exactly, just think of it like 4 diodes in series, clamping the voltage at a certain level for series...and just one big diode for parallel. obviously, it's just plain easier with parallel

.

superdeformed · Post by **superdeformed** » Wed Nov 09, 2005 2:39 pm

Parallel is easier to deal with (mentally

), and in the case of using them for backlighting, parallel is better. Since LEDs aren't perfect, they can use slightly different voltages or currents. So in series there might be a slight drop in power after each LED (aside from what the LED would ideally use), which can cause each successive LED to be slightly dimmer. In parallel, all of the LEDs are pretty much equally bright (or dim, if you don't have enough power/current).

Foxx373 · Post by **Foxx373** » Wed Nov 09, 2005 11:38 pm

Parallel splits the power, series splits the voltage.

There are LEDs that are designed to flash on and off. Try to hook that one LED up by itself to a battery and see if it flashes or not.

Post by **Gamelver** » Thu Nov 10, 2005 12:43 pm

oh yeah, for most 3mm white leds, the voltage is around 3.6V, so when added in series the supply voltage would have to be 14.4V or higher....at least, I think it should

.

oh, and does the led flash completely on and off, or does it just vary the brightness level?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Thu Nov 10, 2005 2:28 pm

sometimes mine just vary