If you want to apply a current to a liquid, such as mercury, and want to observe the change of potential, you need a device that can control the former and measure the latter. Such a device is called a galvanostat.
The word galvanostat comes from an Italian scholar named Luigi Galvani (1737-1798). He discovered that a difference in electronic charge (potential) causes motion. His work is known as a basis for the invention of the battery.
How does a galvanostat work?
A galvanostat is capable of increasing or decreasing a potential in a fluid substance by applying a stable electron current. When there is a difference in the potential between the galvanostat and the liquid, the potential will want to level itself, which will cause the potential in the liquid to drop or increase. The measurement shows how this affects the potential of the liquid (how quickly the potential decreases in time).
Galvanostats are sometimes applied as battery chargers. For example, researchers want to know how long a particular battery will last. They will test this by constantly recharging and emptying the battery. So a battery charger that consumers use at home is also a kind of galvanostat.
Another application is when the resilience of a certain protective layer needs to be determined. By applying an electron current on the layer, you can measure how large the potential of the layer is and how it will behave in different circumstances.
Without software, a galvanostat is of no use. You want to see the measurements in a graph. The PalmSens4 galvanostat is sold including its own easy-to-use software, which allows you to run right away. But you can also use all common spreadsheet software suitable for creating graphs.
The cost of a galvanostat can be pretty high. However PalmSens managed to develop a galvanostat that is highly affordable, especially considering its specifications.