Understanding electricity can sometimes be difficult. The main reason for this is that we cannot see electricity and consequently it is hard to understand something, which is intangible. We just know that when we turn the switch on, the light will turn on, or the fan will start turning. To understand electricity, one must have a basic understanding of three simple electrical terms: volts, amps, and resistance. To assist in imparting a basic understanding of these terms, a simple household water hose example is presented.
Now consider the water flowing through the hose. You could place a one-gallon bucket at the end of the hose and time how long it takes to fill the bucket. For our example, let us say that it takes 30 seconds. This would equate to a water flow rate of two gallons per minute. In electrical circuits, the amount of electricity flowing through a conductor is measured in amps. Getting more technical than this at this time is not necessary for this discussion. When you think of electrical current flow, think of water flowing through a hose (gallons per minute), which is measured in amps.
Each substance known to man has an electrical resistance characteristic. Whether one is considering water, soil, metal, wood, air, etc., there is an electrical resistance to current flow, measured in “ohms”, that describes that particular condition. Everyone knows that the metal copper is conductive and offers a very low resistance to electrical current flow. Now consider air. It is highly resistive to current flow. However, if you supply an automobile´s spark plug with enough voltage, a spark can be made to jump through the air gap between the sparkplug´s two metal electrodes, resulting in a short burst of electrical current flow through air. In this example of forcing electricity to flow through a non-conductive substance, an extremely high voltage was applied, which exceeded the dielectric strength of the substance, resulting in electrical current flowing. The dielectric strength of a substance is similar to or equates to resistance. In electrical circuit terminology, the word “resistance” and the word “impedance” are often use interchangeably.