KARPEN PILE

[pomodoro]

Gentlemen the gadget has been tested.....

Check out the preliminary results on youtube.

http://youtu.be/JpVPrLw9e04


The cell utilizes palladized platinum on the left  and a silver electrode on the right.
Hydrogen gas is bubbled through the 1 molar potassium hydroxide solution.

The high impedance millivolt meter displays the emf between electrodes.  It stabilized at about -900mV.  The minus meaning that the Pd/Pt was more negative.  When shorted through the multimeter, a current in the milliamp range resulted, but for a short time, and then stabilized in the range of tens of uA.  Please note that the meter was found to be not all that accurate later, but be assured that milliamps are initially discharged, as I later slamdunked a 1mA meter with ease.

By monitoring individual voltages I also discovered that it is  only the silver electrode that depolarizes the discharge. The Pd/Pt voltage hardly falters during discharge.
The more negative potential on the Pd/Pt indicates that oxidation occurs there,  and it is unlikely that any silver gets oxidized during the discharge. 

Please discuss or the experiments will end...

[MarkE]

Nice set-up and work!

So, from what I can tell electrically:  The cell maxed out at 955mV terminal voltage with an effective open circuit load, discharged to a couple hundred mV when shorted through the 2K or so of the meter , and then slowly recovered back towards 955mV after the load was removed.  My very simple equivalent circuit model of that behavior is below.

R1 is much larger than R2.  If maybe you had some banana jumpers and clips we could see the terminal voltage when connected to the mA meter so as to estimate R2.  Then we could use the recovery curve to estimate the R1*C time constant.  If the timing were well monitored along with the terminal voltage values I think we could derive pretty good estimate for:  R1, R2, and C.

[profitis]

Dammit I can't get the vid on my blackberry to open.can you put the vid up over here on the forum pomodoro or onto tubidy.com or I'm going to have to wait until I get to internet cafe.so what does this mean pomodoro.was the experiment successful? Where is the voltage now.what is the current at top of discharge curve now.did you let it rest.

[pomodoro]

Cheers.

Umm I didn't check the meter's impedance. I assumed it was closer to just a few ohms as it was in current measurement mode. I also tried a digital meter with similar results. The time to recover to 912mv was 5 minutes.

The voltage recover each time and much more quickly if the hydrogen is bubbled furiously. It still recovers with h2 passed on top only, but slowly.

When it was nearly equilibrated at -906mv the Pt measured -997 and the Ag -83 . Take away the 190 mv from the ref electrode and you get -800 mv which matches the expected potential at pH 14.  Shorting the electrodes makes the Ag polarize to the Pt electrode potential, current flows. 30 uA in one test was continuously flowing after the discharge.

[profitis]

And the current bursts are definitely in the milliamp range inbetween decent rest correct pomodoro?