All successful relationships rely on both parties getting on with each other, and this is just as true for relationships between electrical systems as it is for humans.
The key to this is electromagnetic compatibility (EMC), the maintenance of which is of great concern to electrical device manufacturers.
But what exactly is EMC, why is it so important, and how can EMC issues be avoided?
What is EMC?
EMC refers to the ability of different electrical systems to operate in the same electromagnetic environment. All electronic devices have the potential to emit EM radiation, and with the increasing proliferation of such devices in everyday life, there is massive potential for them to interfere with each other. This is what EMC aims to prevent.
Generally speaking, this is achieved when an electrical device emits EM radiation under certain limits (generally outlined in the law) and isn’t impacted by exposure to specified amounts of radiation itself.
Why is EMC important?
EMC is important as it ensures an electrical device’s external signals don’t interfere with the operation of another device, which can stop it working properly.
A common example of insufficient EMC is when you put a phone close to a speaker and hear an awkward hum or buzzing sound. This is because stray EM radiation sent by the phone to the cell tower is detected and amplified by the speaker, as this has interfered with its circuit. Other examples of EM interference include a broken kitchen microwave causing a computer to reboot or old wireless telephones causing Wi-Fi to drop.
Because of the risk of such occurrences, most countries have regulations around the amount of radiation different devices can emit, as well as how much interference they can handle. These relate to so many components of an electrical device, from the fuse to the power supply.
For example, as XP Power notes: “Power supplies that fail to meet EMC standards cause serious issues in customer equipment.” Electrical manufacturers therefore need to closely consider these regulations during production.
How can manufacturers solve EMC problems?
Although improving EMC immunity is important, the primary way of solving EMC problems is by curbing EM emissions, as this is the main reason devices fail during the product testing stage. There are two ways of doing this.
Removing emissions at source
One way manufacturers can remove EM emissions at source is by adding extra components to a circuit, like resistors, capacitors, and inductors. For example, decoupling capacitors prevent both switching noise and emissions by stopping electrical energy from transferring from one part of a circuit to another.
Absorbing emissions
It’s not always possible to remove emissions entirely, meaning that the best solution is often to absorb them before they reach other components. The most common way of doing so is via Faraday cages that either surround certain components or an entire device, though metal shielding and power planes are also regularly used to absorb emissions.
Final thoughts
EMC is absolutely vital to the harmonious operation of different electronics, yet it isn’t always easy to achieve. Thankfully though, there are lots of solutions in place to reduce EM interference, and extensive regulation to ensure manufacturers produce devices that include these measures.
