stable conductive liquid

T

theyangster

Gawd
Joined
Oct 27, 2004
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I know this seems a little odd, but I need an stable CONDUCTIVE liquid for a little project
involving LED's (If you really want to know, ask :) )

salt water isn't suitable for long term, due to split molecules

critera
clear
cheap
stable (wouldn't release gas,explode)
higher the conductivity the better

thanks
 
That's a tough one. The first one that comes to mind is good ol' mercury, but that's not exactly safe, and getting a large quantity would pose a problem.

Pretty much any solution in water won't work, for the same reasons salt water is undesirable--all those wonderfully energetic ions like to react with stuff, particularly metals.
 
Most water/antifreeze solutions are conductive... conductive enough to use for a 'no water' detection circuit, but nowhere near conductive enough to carry current to a LED or anything.

Post what your idea is, we'll suggest some other ideas.
 
you wouldn't carry the current through the liquid anyways, it would be better to use an amplifier like a couple mosfets or an op-amp.
most liquids that would carry current would be corrosive. mercury is the only solution i can think of that would last.
 
Mohonri said:
That's a tough one. The first one that comes to mind is good ol' mercury, but that's not exactly safe, and getting a large quantity would pose a problem.
QUOTE]

I used to have about about a cup of mercury that I kept in a jar (around four pounds). It was fun to play with it... roll it around the table or across the floor, pour from hand to hand, etc. It's a real pain to clean up if it breaks into small beads tho. No wundr I R a drain bamaged idiot.
Click to expand...
 
they sell "liquid copper" and "liquid aluminum" at auto stores for use in radiator repair, that stuff is bound to be conductive.
 
Yeah, post your application. Based on what you have posted i think you are just going to have to accept "split molecules" is because those, ions, are what give salt water their conductivity in the first place. The only thing liquid I can think of off the top of my head with lots of spare electrons would be some sort of liquid metal.

And what makes you think 'split molecules' are bad at all? If your container is made of pvc or something its not going to corrode, and your wire is made of a metal with a lower salt [chemical quantity, don't remember the term] the water won't try to make it into metal salts.
 
hmmm these answers are not looking good :(

ok here goes
this a more of "can it be done" project (so I'm not considered crazy ;) )

basically I have three layers of plexiglas
the top plate has embedded LEDs in a random placement
the positve lead is in between the first and second layers
the negative lead goes to bottom inbetween the second and third
and of course is sealed with silicone to prevent shorting

the top conductive liquid is positvely electrified
the bottom liquid is negatively electrified
the whole thing will be sealed (with a hole to fill/drain)

hope you get it

EDIT- I guess I'll just have to go with some sort of electrified salt water(something that would inhibit bacterial growth) and refill it periodically
and remember it needs to be clear for maximum effect


please don't suggest using very thin wire or anything else
just liquid sugestions :)
 
looks good and fits my purpose, but 900/kg is abit steep
I know I'd need a small quantity, but NEXT ;)

o and one more thing, the operating voltages will be between 5v and 12v
 
You want the tranparent liquid to be like the wire for the LEDs, right? If that is the case, then you can consider the project quite difficult. I do not know of any ionic solutions that don't have a fair bit of internal resistance. You would have to use a fairly high voltage to get enough current to flow. Even then, the brightness of the LEDs would depend on the distance from the terminals as a small anount of distance would translate to a lot of resistance. If possible, you may be better off with a very thin wire instead.

Hmm ... I just poured some warm water into a small cup and resistance between the two poles about 1" apart is ~10K. With salt added, resistance is about 2K. To get enough power to light a regular led (20mA) you would need:
V=IR=0.020 * 2000 = 40 volts per inch distance of salt solution.
If your led wires are more than about 1/10" away, you will start to develop electrolysis of the water.
 
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