lemon powered clock won't run

[GrandanB]

We have a circuit. The potential voltage of the circuit is 2.2v (with 4 lemons) and our clock should run on approx 1.2v. When we measure the IR drop across the clock, we get a 0.5v drop. We have tried several clocks, both analog and digital, and cannot make this work. What could be wrong (in addition to the short circuit performing the experiment)?

We are at a total loss now, having attempted every variation of correction we can conceive with our limited knowledge of the issue... please help. This is a major part of the grade for this 9th grade class.

[Cap'n Refsmmat]

Have you made sure you're connecting the right wires to the right terminals?

 

What I mean is that lemons don't exactly have + and - marked on each end like a battery does, so you have to figure out which wire is plus and which is minus. Try connecting them the other way around, to the other battery terminals.

[GrandanB]

Yes, we have tried this, and to no avail, but, you know what, we are now in the process of trying yet again. Nothing ventured, nothing gained. Thanxx for this, and any additional help you .. OR ANYONE .. might offer will be cherished. This is supposed to be simple and it's really starting to make me feel stupid.

[insane_alien]

i suspect your lemons are incapable of producing the required current, try adding some in parallel.

 

EDIT: interesting thought on this, perhaps your lemons are lemons at being lemons?

 

EDIT2: dear god i think excessive studying has finally driven me insane

[oicu812]

Make sure you connect the "batteries" in series, that is +[]- +[]- +[]- +[]-

so that their voltages are summed. For example, if you are using copper and zinc strips for your nodes with one copper and one zinc in each lemon, then connect the copper strip of one lemon to the zinc strip of the next lemon, so that you have a copper strip and one end of the series and a zinc strip at the other end. The potential between these two extremes should be the sum of the individual voltages across each cell.

Hopefully you have a voltmeter to check your setup.

[swansont]

Is the 2.2V drop while a load is in place? Or is it just the lemons?

 

Batteries have an internal resistance, so the measurement of a bare battery's voltage doesn't tell you how much it actually will deliver to a load. You can try using a resistor, to ensure that the clock isn't messing up the measurement.

 

http://farside.ph.utexas.edu/teaching/316/lectures/node57.html

[GrandanB]

This idea of running the lemons in parallel intrigues me. We will give it a try. LOL Now we have to run to the store and buy some more lemons Thanks again for your help. You folks are great.

[Mr Skeptic]

What I mean is that lemons don't exactly have + and - marked on each end like a battery does, so you have to figure out which wire is plus and which is minus.

 

I thought that they were clearly marked with the copper as + and the zinc as - ?

 

Anyhow, there is a wiki page for lemon batteries. It suggests running an LED from the lemons.

 

http://en.wikipedia.org/wiki/Lemon_battery