Tuesday, November 27, 2012

A home-made Voltaic Pile

Back from my trip to Italy and visit to Tempio Voltiano I decided that I really ought to make my own Voltaic Pile. So, I gathered together the following easy to obtain items: British 2p coins, zinc coated disks of metal, some blotting paper and a bottle of vinegar.

The British 2p coins are copper (at least on the outside) and so, with the zinc disks, will make the two electrodes of each cell in the pile. The vinegar is the electrolyte and the blotting paper is used to separate the metals. I got the zinc disks by buying the cheapest electrical junction box I could find and punching out all the holes:

Each cell consists of a 2p coin, a piece of blotting paper soaked in vinegar and a zinc disk:

Each cell gave roughly 1.02v (apparently zinc-copper should be 1.1v at 25C) and then it's just a question of making a pile of them to make a larger voltage. This pile of 10 cells had a measured voltage of 9.7v (clearly not all the cells are at 1.02v).


And there's sufficient current to light an LED:


To make it easier to connect to the bottom of the pile I sat the whole thing on a small piece of aluminium foil.

If you enjoyed this blog post, you might enjoy my travel book for people interested in science and technology: The Geek Atlas. Signed copies of The Geek Atlas are available.

2 Comments:

OpenID martinbudden said...

Minor error, you state:

"Each cell consists of a 2p coin, a piece of blotting paper soaked in vinegar and a 2p coin"

presumably one of those 2p coins should be a zinc disc.

2:47 PM  
Blogger John Graham-Cumming said...

Oops; thanks; tixed.

2:50 PM  

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