AC-DC Power Adapter Introduction

An AC-DC power supply or adapter is an electrical device that obtains electricity from a grid-based power supply and converts it into a different current, frequency, and voltage. AC-DC power adapters are necessary to provide the right power that an electrical component needs. AC-DC power adapters deliver electricity to devices that would typically run on batteries or have no other power source.

What is an AC-DC power adapter?
In a nutshell, an AC-DC power adapter converts one type of electricity AC - “alternating current” into DC - “direct current.”  Most people will undoubtedly use electrical devices that require both types of electricity. For example, your car requires a 12v DC electricity supply to operate. And mains power gets supplied to homes and businesses from an AC electricity supply. Sometimes you’ll need to convert AC to DC, and that’s why you’ll need an AC-DC power adapter.

What is AC power?
AC or Alternating Current is the standard type of electricity supplied from the electrical grid to homes and businesses. It’s called AC because of the waveform that the electrons take. Sometimes, the current inverts and changes its magnitude. AC power’s voltage and frequencies differ between regions; for example, the United States uses 120 volts at a frequency of 60 Hz. Across the Atlantic, the United Kingdom uses 230 volts at a frequency of 50 Hz. Because AC power moves in waves, it can travel a lot further than DC power, hence why it gets used in electrical grid systems across the world. While many electrical devices use main-supplied AC power, others need converting to DC electricity. 

What is DC power?
DC or Direct Current is the other type of electricity used in various applications. Unlike AC, the path that electrons take in DC power is linear. You’ll find electrical devices like batteries, solar and fuel cells, and alternators use DC electricity instead of AC. An advantage DC power has over AC is its consistent delivery of voltage to electrical devices. However, a disadvantage of DC power is that it can only run across short distances, making it unsuitable for the electrical grid.Most electronic items require DC electricity due to the ‘clean’ delivery of power. Of course, mains electricity gets provided as AC power, so an AC-DC power supply converts the electricity to DC power. All AC-DC power supplies have rectifiers built into them and transformers to raise or lower voltage levels where necessary. Rectifiers are the components in power supplies that convert AC power to DC. 

Why are there two different power types?
Both AC and DC electricity have their advantages and limitations, and that’s why they get used equally in various electric applications. AC power is an excellent way to deliver electricity over long distances and is suitable for distribution via a mains grid system.DC power provides a more linear and reliable form of electricity, but at the cost of distance. It’s clear that AC power dominates the electrical world, but DC power is a must when powering electronic items at home or in the workplace.

How does an AC-DC power adapter work?
An AC-DC power adapter is a necessity for today’s electronic devices. You’ll find them in various formats, such as external adapters that plug into laptop computers, and internal converters like in all electronics from DVD players to medical equipment. Each AC-DC power adapter will have different design configurations, but the basic principles remain the same. For instance, an AC-DC power adapter will have one or more transformers, rectifiers, and filters. Transformers are passive electrical devices that transfer electricity from one circuit to another. Their job in an AC-DC power adapter is to increase or decrease voltage levels when necessary to provide a reliable source of DC electricity to a device. Rectifiers take AC electricity from a source (such as mains power) and convert that energy into DC electricity. And the job of filters is to remove electronic ‘noise’ from low and high AC power waves.

What happens if you don’t use an AC-DC power adapter?
While it’s true that some household and commercial electrical items only use AC power, many other applications demand DC power. What happens if you try to supply AC power to an electrical device that requires DC electricity? The short answer is simple: terrible things will happen! Electrical devices with electronic components will almost certainly get destroyed, and some high AC voltage equipment may even explode or catch fire. There’s also the risk to human life if you apply AC power to an electrical device that requires Direct Current. That’s why it’s always essential to use an AC-DC power adapter when the electrical requirements demand it.