Terms You Need to Know
What is a "volt?" A Volt is a unit of measure of the electrical force that seems to push the current along.
Think of voltage as the amount of water (potential energy) stored in a high water tank (battery) on top of a hill.
Because the water tank is full and high up, the water will contain more potential energy and pressure causing the water to flow more rapidly. If the same tank was placed at ground level, your water the same amount of water would not flow as fast. The symbols commonly used for voltage are "E" or "V".
What is an "ampere?" An ampere is a unit of measure of the amount of electricity flowing through the circuit. Amperage is often referred to as "current" by electrical workers and engineers. The symbol for amperage is "I"
Let's go back to our water tank.
- If the diameter of your pipe coming from the water tank is large, a lot of water (amperage/current) will quickly flow through the pipe.
- If the pipe's diameter is small, less water is able to flow through the pipe.
What does this all mean? If you need a lot of current (many amps) to operate your equipment, you'll need to use larger wires to handle the additional current or they'll burn up!
What is an "ohm?" Think of an ohm as "resistance". An ohm is the unit of measure for the opposition (resistance) to the flow of electrical current. The symbol for resistance is "R".
Using our water analogy: A small water pipe is going to oppose or resist a lot of water from flowing. Relatively little water will be able to flow through the pipe. You can see that a large pipe would offer little resistance to the flow of water. Big pipe: a lot of water! It's that simple. In an electrical circuit, components are usually sources of resistance. Any component that heats up due to electrical current is a source of resistance.
What is a "series" circuit? The current in a series circuit flows along one path through a number of resistance sources in that one path. For example, water from the tank may flow down one pipe that spins electrical generators along the way until it eventually reaches the ocean.
What is a "parallel" circuit? The current in a parallel circuit takes many paths to get back to the battery. For example, the water flowing from a water tank up on a hill will split off into many different water pipes (parallel) before it reaches the ocean.
Knowledge Check Choose the best answer for the question.
1-3. What is the unit used to measure the resistance to the flow of electrical current?
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