keyboards

What's the resistivity of that ?

Graham

Isn't rubbing alcohol about 90% isopropanol and 10% water ? The water could have dissolved some crud and moved to somewhere it did more harm.

Graham

My 'argument' was over these of the word short. That means a low resistance to me.

You don't however need a low resistance to cause a malfunction.

Graham

I assume you mean dissolve but I rather doubt that's likely.

Graham

"Eeyore" wrote in message news: snipped-for-privacy@REMOVETHIS.hotmail.com...

Depends on the materials used.

ah, only because its too hot!

"Eeyore" wrote in message news: snipped-for-privacy@REMOVETHIS.hotmail.com...

I don't think liquids follow ohms law but just look at any chemical battery(dry cells). They use liquids and have an internal resistance of a few ohms. Electronic flow is not due to the liquid itself(in some sense) but the interaction of the ions in the liquid with the electrodes.

"Eeyore" wrote in message news: snipped-for-privacy@REMOVETHIS.hotmail.com...

well, current cannot flow without with infinite resistance. Voltage doesn't make sense without current(look at the definition). Any time you measure voltage you are really measuring how electrons flow(just the current is extremly small... you theoretically only need 1 electron). Low resistance is a relative term. Is your circuit is operating at 1M volts then something that has a resistance of a 10k ohms thrown across two points could cause it to short... as could 10k ohms thrown across something with a working voltage of about 10V.

short circuitElectricity an abnormal, usually unintentional condition of relatively low resistance between two points of different potential in a circuit, usually resulting in a flow of excess current.

the main thing here is not low resistance but excess current. That could be a few milliamps for some devices or many amps for others. Throw a solution of salt water on a circuit board and chances are you will create a short somewhere that will ruin some component and hence ruin the whole circuit.

true. I don't think I ever said you had to have it? I just said that voltage wasn't enough to do anything. Are you afraid of standing in a water puddle with without any shoes soaking wet while playing with an AA battery? What about a tazer(which might use an AA battery but thats not the point)?

Keyboard skin:

Ed

It will conduct 1000 times the current at 1000 volts as opposed to 1 volt. I have moved and rebuilt a RCA TTU-25B 25 KW UHF TV transmitter that had 7000 VDC on parts of the water cooling system. The slightest contamination would cause the water to electrolyze. If it got out of control, it could blow the rubber isolation piping apart. To prevent this, there was a constant monitoring of the water, and if the resistance started to drop, it shut down the B+.

Jon, it's far more likely that the liquid has ruined the traces on the mylar that forms the keyboard circuit board. Often there are two layers that are formed by folding the mylar. These are easily broken but small section can be touched up with conductive paint (silver print).

On Sun, 3 Sep 2006 13:50:11 -0500, in message , "Jon Slaughter" scribed:

:True, but liquids are not conductors at low voltages in general? (i.e., any :non electrolytic solutions).

Your question appears to have been answered well by other posters. My take is that the problem can be either one of two causes. Let's consider the possibilities. First, the circuit matrix of the keyboard is likely composed of high-conductance carbon strips painted on plastic sheeting. The voltage is likely 5V between on and off states. Currents are low. Second, a user is not likely to spill non-electrolytic water on a keyboard. Rather, it's likely to be coffee, soda-pop, or even beer. These liquids all have two things in common - high conductivity and chemical corrosivity.

My experience with broken keyboards is that many times they can be cleaned with distilled water (non-electrolytic) and put back into service. This works if the problem was caused by short-circuit conductivity between tracks, which is a possibility even in light of the low power involved.

Other experience has shown me that the corrosivity of the spilled liquid will dissolve carbon tracks and produce open circuits (as posted by Lord Garth). This outcome is most likely with cheaper keyboards which are not meant to be used in a harsh environment.

Alan B wrote in news: snipped-for-privacy@4ax.com:

Oh no! Not beer!

Puckdropper ;-)

-- Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

Orange juice is the worst!

I wonder if Jon can accept practicing safer typing by using the (formerly widely available) 'keyboard condom'? These were plastic covers for particular keyboards that form fit each key. The only place I have seen them recently was on the keyboards used in automotive repair shops.

'keyboard skins'

The recommended retail price of Seal'n Type is $14.95(US) or $19.95(CDN) or £14.95(GB) ex works

On 04 Sep 2006 16:36:55 GMT, in message , Puckdropper scribed:

Whatever you do, don't spill peppermint schnapps. The keyboard will stick to your fingers, and the ants will be all over the place.