What is commonly referred to as Potential is in fact a potential difference: the difference between the potential at one point and the potential at another point, such as in the two ends of a battery (Figure 1).

Figure 1: Potential difference driving a current.

In electrochemistry the standard hydrogen electrode has under standard conditions a potential of 0V by convention. This is used to give the potential for a single point, because it is referred to the 0 V potential of the standard hydrogen electrode.

Potential applications

When  two points with different potentials are connected to each other, the potential will equalize according to the law of the communicating vessels (Figure 2).

In case of electrical or electrochemical potentials electrons are exchanged between the two points. This electron current is used for example to make electronic devices operate (Figure 3).

Figure 2: Communicating vessels

Figure 3: Electrochemical potential pictured as communicating vessels.

Measuring the potential

A potential can be measured with a voltmeter, as also present in a potentiostat, galvanostat or EIS analyzer.

  • A potentiostat is capable of applying a constant potential to a conducting surface. In contact with another object or liquid this surfaces acts as an electrode. By the potential induced electrochemical reactions cause an electron flow with a certain number of electrons per second. This phenomenon can be used, for example, to detect the presence of certain substances in a liquid. One example for a potentiostat is the EmStat by Palmsens.
  • A galvanostat applies an electron current, which induces a change of the electrodes potential. An example for a galvanostat is the Palmsens4..
  • An EIS analyzer is used to measure the resistance of a (liquid) substance or article by releasing a controlled potential wave and measuring the response to it. These measurements can also be made with the Palmsens4.
A potential is nothing other than the voltage or electrical voltage of a specific (liquid) substance.