Difference between AC and DC Electrical Currents

Tesla’s Alternating Current (AC) and Edison’s Direct Current (DC) describe the flow of electrical charge. The main difference between AC and DC goes beyond the people who discovered them, though. The importance of their differences lies in their mechanics. Let’s dive into the nitty-gritty, the differences between AC and DC electrical currents.

Alternating Current (AC)

Alternating Current (AC) is an electrical charge that periodically changes direction. The change in the direction of AC electrical currents is due to electrons that move in both positive (upwards) and negative (downwards) directions. Typically, the flow of electrons in both directions in an alternating current creates waveforms.

The rate at which alternating current changes direction is its frequency, expressed in Hertz (Hz). The standard frequency for household currents differs from country to country. In the United States, the frequency for household currents is 60Hz, while that of European households is 50 Hz.

The main advantage of AC is that it can easily travel over long distances. An example of AC is the residential and commercial power most of us use.

How AC is Produced

Alternators and electric generators produce AC by rotating a wire loop in a magnetic field. When the wire moves into different magnetic field areas, the magnetic field’s varying strength creates a force that drives electric charges around the wire in a wave-like motion.

Applications of AC

As earlier mentioned, generating and transporting AC over long distances is relatively easy. Most household appliances, including lamps, washing machines, and refrigerators, use AC power. It is also easy to convert AC from high to low voltages and vice versa using transformers.

AC is also used to power simple AC generators and electric motors. The main difference between the two devices is that motors convert electrical energy into mechanical energy. Generators convert mechanical energy into electrical energy.

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Direct Current (DC)

Direct Current (DC) flows in a linear direction. Some examples of sources of DC include solar cells, fuel cells, batteries, and some types of alternators.

How DC is Produced

There are several ways to generate DC.

  • You can pair an AC generator with a commutator (a device that reverses electric current direction in the generator’s rotating windings) to produce DC.
  • You can use a rectifier (a device that allows the flow of current in only one direction) to convert AC to DC.
  • You can use batteries to produce DC. Batteries produce DC through a chemical reaction inside the battery.

Applications of DC

Compared to AC, DC power is far more reliable in terms of voltage delivery. Special and sensitive applications like sub-sea high voltage transmission lines use DC. For such transmission lines, electricity is first generated in AC before converting to DC while flowing through a network of cables. The DC then reconverts to AC through a terminal before reaching consumers via power supply lines.


Even though most electronic devices currently use AC because of its ease in transportation and transformation, both forms of electric currents are equally useful. DC is primarily essential to devices like batteries that store power for future use. Gadgets like smartphones, laptops, portable generators, torches, and outdoor CCTV camera systems that are critical for your day-to-day activities all rely on storing DC power.

For instance, when you charge a smartphone from the main electrical supply, you convert AC power to DC power using the rectifier in your phone. This proves that none of these electrical currents is superior to the other and that, in most cases, we require both.

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