Terms You Need to Know
What is a "volt?" A volt is a unit of measurement for electric potential. It measures the electrical force that drives an electric current between two points.
Think of voltage like a large amount of water stored in a high water tank. The higher position of the water tank ensures that the water has more force as it flows down the pipe to your home, similar to how voltage drives electric current. This is the reason water tanks are often placed at elevated heights. If the same tank were at ground level, the water pressure would be significantly lower. By the way, the symbols commonly used for voltage are "E" or "V".
What is an "ampere?" An ampere is the unit used to measure the amount of electrical current. Amperage is often referred to as "current" by electrical workers and engineers. The symbol for amperage is "I".
Returning to our water tank analogy, think of the diameter of the pipe coming from the tank. If the pipe is large, a greater amount of water (representing amperage) will flow through it. Conversely, if the pipe is narrow, less water flows through. Similarly, in electrical terms, if your equipment requires a substantial amount of current (many amps), larger wires are necessary to carry the current safely. Without adequately sized wires, there's a risk of them overheating or burning up.
Current takes two basic paths in a circuit: series and parallel.
- The current in a series circuit follows only one path. For example, imagine water flowing from the mountains down a single stream (series) into a river, and then to the ocean.
- The current in a parallel circuit takes many paths. This is similar to water flowing from a hilltop tank through various pipes (parallel paths) before reaching the ocean.
What is an "ohm?" An ohm is a unit of measurement that represents the resistance to the flow of an electrical current.
In an electrical circuit, components often act as sources of resistance. A component that generates heat when electrical current passes through it is a source of resistance. The symbol used to represent resistance is 'R'.
For instance, a small water pipe will restrict the flow of water, allowing only a limited amount through. This means that a smaller pipe presents higher resistance to water flow. Conversely, a larger pipe allows more water to pass through easily, offering lower resistance to the flow.
Knowledge Check Choose the best answer for the question.
1-3. Which of the following is the unit used to measure the resistance to the flow of electrical current?
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