Definition - What does Potential Difference mean?
Potential difference can be defined as the difference in potential between two or more separate systems such as rails and pipes or earth and pipes connected through an electric circuit. The unit of measurement is Volt (V). It is measured between two different structures or between the earth and a structure. Soil resistivity test uses this principle for investigating soil in order to understand soil characteristics and tendency of corrosion in buried pipelines.
Trenchlesspedia explains Potential Difference
To measure potential difference across a component, a voltmeter is arranged in parallel to the component. The difference in energy from one side of the component to the other is the potential difference. Soil resistivity test is carried out using the Wenner 4-point test which requires four spikes arranged equidistant and in a straight line in the earth. The current probes are the spikes at the two ends while the potential probes are the two middle spikes.
A known current is passed between the current probes and the potential difference is measured between the potential probes.