We're sorry, but OSHAcademy doesn't work properly without JavaScript enabled. Please turn on JavaScript or install a browser that supports Javascript.

715 Electrical Safety for Technicians and Supervisors
Skip to main content

Terms you Need to Know

What is a "volt"?

A Volt is a measure of the electrical force that seems to push the current along.

Use Ohm's Law to determine power, voltage, current, and resistance. Examples: P=IxE, I=E/R.

Think of voltage as a lot of water stored in a high water tank. Because the water tank is high, the water will have more force behind it as it flows down the water pipe to your home. This is why they put water tanks up high! :-) If the same tank was placed at ground level, your water pressure would not be as great. By the way, the symbol for voltage is either "E" or "V".

What is a "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. 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) will flow through the pipe. If the pipe's diameter is small, a smaller amount of water will flow through the pipe. If you need a lot of current (many amps) to operate your equipment, you'll need large wires to run the current or they'll burn up! The symbol for amperage is "I".

What is an "ohm"?

Think of an ohm as "resistance". An ohm is the unit used to measure the opposition (resistance) to the flow of electrical current. This is pretty easy to understand.

  • A small water pipe is going to oppose a lot of water from flowing. Relatively little water will be able to flow through the pipe. So, the pipe offers a high resistance to the flow of water.
  • A large pipe would offer little resistance to the flow of water. Big pipe: a lot of water! It's that simple.
The current in a parallel circuit takes many paths.

In an electrical circuit, components are usually sources of resistance. Any component that heats up due to electrical current is a source of resistance. The symbol for resistance is "R".

What is a "series" circuit?

The current in a series circuit takes only one path. For example, water from high in the mountains may flow down one stream (series) into a river that flows to the ocean.

What is a "parallel" circuit?

The current in a parallel circuit takes many paths. For example, the water flowing from a water tank up on a hill will flow through many different water pipes (parallel) before it reaches the ocean. The total amount of water will be divided among each path.

Knowledge Check Choose the best answer for the question.

1-3. Which of the following is a measure of the electrical force that seems to push the current along?