Understanding Ohms Law

Today we are going to talk about ohms law, one of the most basic formulas in the electrician’s tool box. Ohms law is a formula that describes the relationship between voltage, current, and resistance in an electrical circuit. In the electrical trade we use many different formulas for a variety of situations that exist, but ohms law is the one formula that is used most often.

ohms law triangle

We will now take a closer look at how all of this works. The basic premise is that it takes one volt to push one amp through 1 ohm of resistance. Did that sound a little bit confusing? If so let’s look at it from a different perspective. Let us first take a look at voltage represented by the letters E or V. Voltage can be considered as the pressure that is used to push current through the conductor. Imagine a water hose, the hose being the conductor, voltage would be the pressure of the water running through the hose expressed in psi (pounds per square inch).


Let us move on to current represented by the letters I or A. In the water hose analogy current would be represented by the amount of water flowing through the hose expressed in gpm (gallons per minute). Last but not least we have resistance represented by the letter R or the greek letter omega, sorry but I have no idea how to make the greek letter omega from the keyboard.


Resistance could be looked at as the size or diameter of the hose. The larger the hose the more water we have, the smaller the hose the less water you get the idea. In an electrical circuit current is directly proportional to voltage and inversely proportional to resistance. Now to say the same thing in a different way, if you increase voltage you increase current and vice versa if you decrease voltage you decrease current. However if you increase resistance you decrease current and if you decrease resistance you increase current.

ohms law formulas

These are the relationships that are expressed in the ohms law formulas and by understanding these relationships we are able to better understand how electricity works in a basic circuit. As always I hope this article was helpful, however you can find a wealth of information on the web about ohms law to gain a different perspective on the subject. I will submit articles in the future that will give more useful insights into the various tools that are used in the electrical trade.

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