The flow of electricity happens in two main ways: in a direct current (DC) and an alternating current (AC). Both are indispensable in our day-to-day life, but what differentiates them? Which is standard in home electrical systems in the US and why? Keep reading to learn more.

Origins of AC and DC: War of currents

In the 1880s, Nikola Tesla and Thomas Edison were embroiled in a battle currently described as “the war of currents.” Thomas Edison developed a direct current— that moves in a single direction. In the early years of electricity, DC was the standard in the US.

Nikola Tesla, who initially worked for Thomas Edison, developed AC. Supported by George Westinghouse, a wealthy investor, Tesla was able to outwit Edison’s DC project. Please read our article Edison vs. Tesla: The War of Currents for more information on this.

AC vs. DC

Alternating current

As the name implies, it is electricity that oscillates back and forth and constantly changes with time. It can be converted to different voltages (high and low voltages) efficiently using the transformer. This change of voltage makes it possible for AC power to be used for long-distance transmission over DC, which is a huge benefit when it comes to delivering power to consumers. It is transmitted at high voltages precisely to reduce energy losses along the way. The high voltage is then transformed into a relatively safe voltage for domestic uses.

Most household appliances and consumer electronics such as coolers, refrigerators, fans, washing machines, lamps, etc., rely on AC power tapped from the power grid via power outlets.

Direct current

As you may derive from the name, DC is electricity that flows steadily in one direction. It is more consistent in terms of voltage delivery, and it is for that reason, some electronics depend on and use it. Some electronic devices use a rectifier to convert AC to DC.

DC is expensive to distribute. To distribute it, electronic circuits are needed to yield AC that is then transformed with a transformer and corrected back to DC. This explains why AC is preferred when it comes to power transmission. The inability to convert DC to high voltage for transmission was the key reason why Tesla developed AC. At that time, it wasn’t easy to change the voltage of DC electricity, and that is how AC quickly became a standard in the US.

Applications of Direct Current

  • Used in low-voltage small electronic devices and gadgets such as cell phones, laptops, radio, etc.
  • LED lighting
  • Solar Power Systems
  • Battery storage systems
  • Home Security Systems
  • Currently, used in Electric Vehicles (EVs), Hybrid Electric Vehicles (HEVs), and automobiles. With the rapid depletion of petroleum resources, EVs, HEVs, and fuel cell electric vehicles are slowly replacing conventional vehicles.

Could DC be the wave of the future?

Direct current is slowly coming back. Technologies such as modern LED, solar panels, cell phones, and computers all rely on DC to operate. This creates the need to convert AC to DC voltages for these devices to function. However, about 5 to 10% of energy is lost during conversion.

Further, going by The US Department of Energy’s Power America initiative projection that by the year 2030, an estimated 80% of all US electricity will need conversion from AC to DC. This then arises the need to possibly save more energy if the conversion rate is drastically minimized. So, if things continue to unfold as they are today, DC could be a trend that will inevitably prevail.

Both AC and DC are widely used, and with the use of DC increasing each day, there is a likelihood reliant on the direct current will be a new norm soon. How soon that will happen remains a puzzle that we look forwards to solve.

Got a question about AC vs. DC? Our licensed electricians will be happy to help. Get in touch to speak to one of them about any DC electrical related projects at your home or business.