In this five-part EMC blog series, we will walk you through a basic understanding of EMC. By the end of this series, you should be able to start your designs while keeping EMC concerns in mind up-front.
In this first post, we’ll give you an overview of EMC and how it may concern you and your company. Once you understand what EMC is, we'll then talk about chip bead ferrites and understanding datasheets in our next post. Then we'll move on to defining the losses and details of insertion loss calculation. And finally, we'll finish up with a discussion about clamp-on ferrites.
But first — what is EMC?
First things first: EMC is not to be confused with EMI.
Every electronic device emits EMI, or electromagnetic interference. How that affects your device and other electronic devices is where EMC comes in.
EMC, or electromagnetic compatibility, is concerned with how well your product interacts with other products within its environment.
The world is a busy place, and it's filled with tons of EMI. Your job is to make sure that your device does not cause any unintentional failures to other devices and, at the same time, protect your device from the EMI caused by others.
In short, in order to be electromagnetically compatible, you need to prevent emissions and have high immunity. So please keep this statement in mind as we move forward in the blog series; it will be key to our discussion.
There are many types of electronic devices in the world that provide many types of different applications — that's an obvious thing.
The level of products ranges from very simple to very complicated. The impact of a failure of one of these devices may be harmless, or it may be life-threatening.
Therefore, there are many regulations for EMC to ensure the safety of electronic devices and make sure there aren't any unintentional failures caused by EMI. There are special electronic components for this purpose.
IEC is a worldwide standard, and EN is a European standard. We won't get into the details of every standard here, but we want to show you these very specific regulations for several different industries, such as medical equipment, industrial equipment, information technology, and so on. It is very important that you're aware of what regulations your product needs to meet in order to bring your product to market.
It's not up to manufacturers of EMC components like Würth Elektronik or EMC labs to tell you what standards you need to meet. You will need to know this for yourself when you're getting your product tested at the EMC Lab for certification.
The EMC Lab will definitely be able to point you in the right direction, but at the end of the day, it is your responsibility to understand those standards.
There are a few different types of EMI. Understanding these types will help you identify what might cause any EMI issues you'll encounter.
Here, we're using an old picture as an easy example of what EMI looks like.
On the left, you see a picture taken from an old television. Since it was not designed for EMI, the old TV is very susceptible to EMI and the failures caused in its environment. The picture on the right shows the results of this type of interference.
So put the picture into a real-life scenario: You’re watching TV, and somebody decides to come in and vacuum the living room. The result of the EMI emitted by the vacuum is a distorted screen, like the image on the right. Not a pretty picture.
Luckily, standards have now been put in place to prevent this type of situation.
As stated previously, in order to be electromagnetically compatible, you need to both prevent emission and have high immunity. Emission is concerned with EMI leaving your device, and immunity is concerned with EMI entering your device.
There are two types of each of these: conducted and radiated. Conducted is a direct connection, like a wire or cable, whereas radiated is transmitted through the air.
We like to use the flu example when discussing this topic. Picture a situation in which the flu bug is going around. People may choose to wear surgical masks.
Now, they can wear these for two different reasons. If they have the flu and don't want to spread it to others, they're using this flu mask to prevent emission. If they don't have the flu but don't want to catch it from others, they're using the mask to increase immunity.
Safety In Electronics Design
Safety In Electronics Design
The affect of insulation requirements is significant enough to change the form factor, performance, cost and of course, reliability of the transformer.
To bring a product to the market in Europe you need the CE conformity. An important aspect is the EMC, which is the subject of this blog article.
Common Mode Chokes
Common Mode Chokes
Let's examine the function and operation of a common mode choke and the way it reduces unwanted interference.