well.. i should have clarified in that last post.. my mistake.
a pot is a completely safe addition to the circuit. the only reason i went on a tangent about how they are not a true dimmer, is just so i wouldn't be corrected by somebody else, later down the road and plus i believe in supplying more information on a electronic subject than necessary just to make sure there isn't any confusion later.
a pot would be 100% safe if you build the circuit in parallel with a resistor tied to each led
. the way the system works.. is that electrons flow from the source to the resistor which steps down the voltage, and any incoming current to an acceptable levels for the led
. then the electrons flow into the led
, turn it on.. then return to their source. here's a wiring diagram http://12598.tripod.com/dia3.JPG
. the resistors on the led
's are just doing a coarse voltage/current adjustment. when you install the pot, put it on between the led
/resistors and the source shown in the diagram. the pot will actually do a fine voltage/current adjustment, just dropping enough voltage to get the led
's to turn on, but not to their max output.
the semi complete list of how to destroy an led
[some personally tested!]
exceed their voltage and/or current ratings,
install them in a circuit backwards (opposite polarity) without a limiting resistor
making direct contact with a soldering iron for more than 15seks (which i have done, and they still worked.)
physically damaging them, by cutting, crushing, ect
dunking in water when power is applied (shorting them out)
if you under power them, then they won't turn on (untill more voltage is applied) or they will barely turn on (creating the illusion of a dimmer switch) under powering a electronical device will almost never destroy them, so their is no harm in under powering them, led
's only die when you apply too much
one thing you might want to take a look at, is getting a medium to fit between the led
's and water to diffuse the light. the diffusing plate will actually spread the light through out the entire tank, and avoiding the spotlight effect. you could always use the pot and diffusing plate to really fine tune their output if you wanted. but i would recommend trying the plate idea first alot of people on the forums like that better than the pot, probably because it avoids the spot light effect from the led
sells sheets of plastic that are made to diffuse light produced by a florescent light system, you see those in use alot in commerical buildings and schools. just cut it up to fit, and then install the pot for maximum adjustments. those panes, in my local hd, are right next to plastic eggcrates, that are used for the same purpose too.