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Ohms, Amps, Volts, and What You Need To Know | Quest Components

25 Jun, 2019 | Quest Components
Ohms Law Triangle

Ohms, Amps, Volts, and What You Need to Know

When working with electronics, it is extremely important to understand the basics of electricity. Only then can you properly size your components and ensure that your products are safe. Here is what you need to know about how electrical current is measured.


Measuring Electricity

Electricity has four components. Each is comprised of different units. Knowing what each component is and how it is measured allows you to make all the calculations you need to ensure safety and compatibility between electrical parts.



  • Voltage (V) is measured in volts (V).
  • Current (I) is measured in amps (A).
  • Resistance (R) is measured in ohms (O).
  • Power (P) is measured in watts (W)

Here are the basic rules that define how these measurements work together:

Power = Voltage * Current, or P=V*I

Therefore, you can always calculate voltage, current, or power if you know two of the three values:

I=P/V and V=P/I

Ohm’s law explains the relationship between voltage, current, and resistance:


In other words, the voltage equals the current times the resistance. You can then calculate voltage, current, or resistance if you know the values of two out of three:

R=V/I, or I=V/R


With those equations in mind, let’s take a look at what each component actually is.

Volts: If you consider electricity as the equivalent of water flowing through a pipe, voltage is the water pressure. When a “water pump” in the form of a battery or power connection is applied, the pressure rises, causing the “water,” or electrical current, to flow. As the voltage increases, so does the current.

Household outlets in the United States have a standard voltage output of 120V. A single cell battery has a voltage of 1.2 to 1.6V, while high voltage power lines put out an incredible 110,000 volts.

Amps: Short for ampere, the amp measures electric current. In the water pipe example, current is the flow rate of the water. A larger current, or more amps, indicates that a larger amount of electricity is flowing.

Ohms: Ohms measure resistance in the electrical system. In a water pipe, the pipe adds resistance, controlling the amount and direction of water flow. In an electrical circuit, resistance effectively narrows the pipe, reducing the current.

Watts: Watts measure the total power of the system, or how much energy is released per second. It is affected by both the voltage and the current.

Different electronic components play different roles in controlling the voltage, resistance, current, and overall power of the system. The more you know about these individual parts of the equation, the better you will be able to determine exactly what your project needs.

Ready to Get Started?

Here at Quest Components, we are committed to providing you with the information you need to help your business continue to run smoothly. An ISO 9001:2015 Certified Company headquartered in Industry, CA, Quest Components specializes in passive and active board level components. We also provide a variety of services to OEMs (original equipment manufacturers) and CEMs (contract electronics manufacturers) across the globe. Contact Quest Components today at 626-333-5858 for all your electronic component needs!

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