Currents Rock: Differences in AC and DC Electricity

Ryan M. Creery
Nov 7 · 3 min read

True Story: Recently, I was talking about how solar power energy works with a friend. When I got to the Inverter part of the system (the component that converts DC electricity to AC electricity), I immediately lost them. I noticed it because I’m pretty sure I had that same lost-in-space look in my eyes when it was first explained to me. Before my interest in solar power energy started, my love for Nikola Tesla was burning. How does this relate? Because Tesla was actually one of the first proponents of AC — unlike his nemesis, Thomas Edison.

A Brief History: A Battle of the Volt

In one corner, Thomas Edison, inventor of the standard light bulb, phonograph and movies. He opened the first commercial-use electrical power plant in New York, with celebrated success. But the power generated couldn’t travel very far, which became problematic — they had to build power stations every mile in order to service full neighborhoods.

In the other corner, Nikola Tesla, basically the brains behind our modern versions of mass communication, like radio, cell phones, and television. Determined to outwit and defeat his opponent, Tesla was able to one-up Edison’s systems by created the first hydroelectric plant at Niagara Falls, which was able to send power across 15 miles!

In the end, Tesla’s AC won out because of its efficiency in transmitting electric currents over miles and miles. In the U.S., DC was still the primary source of electricity for years, thanks to Edison’s power (no pun intended). It wasn’t until General Electric’s George Westinghouse invested in AC around the turn of the century that it completely took over DC soon after.

Enough of that, let’s get back to AC versus DC. So, what’s the difference between these two battling opponents and why does it matter? Let’s dive in.

Direct Current — One Flow, One Goal

What is a direct current? Simply put, it’s when the electrical current flows in one direction. Scientifically speaking, it is the constant flow of high-density electrons (the negative end of the battery) to an area of low electron density (the positive end). Anything that uses a battery is a good example of DC power.

Direct current works great for devices, since it can also charge batteries. In fact, rechargeable devices, like laptops and cell phones, come with a charger that has an AC adapter that allows the AC power from the outlet to switch to DC power that the battery can utilize. So, even though we rely heavily on AC electricity, we still use DC in our everyday lives.

Alternating Current — Switch It Up

Opposed to direct current, alternating current constantly reverses the flow of electricity. Those big wires you see stretching from tower to tower carry AC electricity, originating from a power plant that generates electricity, typically using a water source. Pulsing through those wires, currents switch flow 60 times per second! At this incredibly fast rate, even when the flow is reversed from its output location, like a light switch or plugged item, the shift is so fast the device doesn’t have time to turn off. That’s pretty incredible!

AC Terminology

Period — The interval of time between the attainment of a definite value on two successive cycles

Frequency — The number of periods per second

Amplitude — Maximum value in either flow direction

THE WINNER

In the battle of DC vs. AC, who is our reigning champion? Well, both.

In the end, what’s important to remember is that both are necessary for us. If we’re looking at understanding how solar panel systems work, this is a key piece of information for us to know. From the sun, we see that DC electricity is what the panels create. Here’s the catch: Homes and commercial buildings need AC electricity in order to work. There’s a critical part of the system that occurs in order to convert DC to AC: the current is run through an inverter. And that’s how we’re able to use energy created from the sun!

Hopefully this has given you a bit more insight into what differentiates DC and AC electricity. What’re your thoughts?

Written by

Sally Beauty Copy Manager, published poet, avid mystery reader. Denton, Texas is home.

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