AC and DC power supplies are integral when it comes to powering your home – but they’re very different. Here, we simply explain the differences between AC and DC power and why they’re both important.
For an electronic device to work, it requires a power source and supply. A power supply is crucial, as it converts the electrical current from a source (such as the power mains or a solar system) to the voltage and values required to power the device in question.
All power supplies take electric power from the source at input, before transforming it and delivering it to the load at output. This is how your devices receive power and operate when connected to electricity. There are two types of power at input:
- Alternating current (AC)
- Direct current (DC)
Let’s take a closer look at the differences between the two.
Alternating current (AC)
AC is when the electrical current periodically inverts its direction, and is the method employed in the UK when delivering power from transmission lines to homes and businesses in the country.
The current flow of AC alternates between positive and negative due to electrons, which can move up or down – known technically as the sinusoidal AC wave. This wave is a result of alternators at power plants creating AC power.
AC power can travel much further than DC power, which is a huge advantage when it comes to delivering power to homes and businesses throughout the United Kingdom.
Direct current (DC)
DC is when the current flows in the same direction constantly and comes from the likes of solar cells, batteries, fuel cells, and even modified alternators. If you install a rectifier in your home, you can covert AC to DC power.
One of the main benefits of DC power is that it’s much more consistent than AC in terms of voltage delivery, which is why some electronics rely on DC. That being said, many bulky household items in the UK (fridges, washing machines, etc.) run on AC power.
Why do we need AC & DC power?
Both AC and DC power are important and it’s impossible to say which is better than the other. AC dominates the market, as all installed power outlets bring power into buildings via AC from the mains. This can then be converted to DC for specific devices.
The main reason for this is that DC power is not capable of travelling long distances, which is why it’s linked to solar and battery energy storage systems that are installed on site.
A helpful way to look at it is that DC is most commonly linked to solar systems and battery storage, while AC comes from the main electrical grid.
Recap
Both AC and DC power supplies are important and it’s helpful to be aware of the differences between the two, particularly if you’re installing a battery energy storage system or solar PV system at home.
The key takeaway is that AC and DC are both important, but they aren’t the same, and you should always check which power supply a device requires before making a purchase, particularly if your house runs off solar.
