Electricity contains a standard collection of values. Before a person can operate with electricity, it is best to understand these values and realize exactly how to make use of them. Given that values of electrical measurement have been standardized, they will be understood by every person that makes use of them. An example is carpenters, who use a standard system for measuring length, such as the inch, foot, meter, or centimeter. Imagine exactly what a house would look like if it was constructed by multiple carpenters who used different lengths of measure for an inch or foot. Precisely the same holds true for anyone who electricity. The standards of measurement need to be exactly the same for everyone. Meters ought to be calibrated to indicate the same amount of current flow or voltage or resistance. A volt, an ampere, or an ohm is identical everywhere in the world.