What EMC needs to be aware of when testing electronics

EMC test, also known as electromagnetic compatibility (EMC), refers to the comprehensive evaluation of dimensional impact (EMI) and immunity (EMS) of electronic products at the electromagnetic field level. It is one of the most important indicators of product quality. Electromagnetic compatibility measurement consists of test site and test instruments. The purpose of EMC test is to test the impact of electromagnetic radiation on human body, public power grid and other electrical products.

Electromagnetic compatibility is a subject that studies the coexistence of various electrical equipment (including biology) without degradation under the limited space, time and spectral resources. It includes electromagnetic influence and electromagnetic sensitivity. The electromagnetic influence test is to measure the size of the electromagnetic wave signal and reflect the impact on the surrounding electronic products. Electromagnetic sensitivity test is to measure the anti-interference ability of the equipment to be tested against electromagnetic interference. Electromagnetic influence mainly includes radiation transmission and transmission transmission.

What is the average EMC test pass rate of electronic products?

There are few statistics on this topic, because EMC test laboratories and the government do not need to collate information. However, the initial compliance rate of one of the large studies provided by the world-famous TUV testing center is only 50%! Failures can easily take days to months to market, so it is very important to prepare for EMC testing. In this guide, I will explain in detail the preparation process and your EMC should consider the design and pre-compliance test level.

Must we focus on EMC testing?

Although there are some exemptions, if you design, manufacture or import products containing electronic products, you almost certainly need to pay attention to EMC.

What should we pay attention to in EMC testing of electronic products?

1. Maintain electromagnetic spectrum

We have only limited electromagnetic spectrum, which can be used for radio transmission, microwave communication, X-ray optical machines and many other products. Unfortunately, even electronic products without transmitters will send electromagnetic radiation, just like the switching current and voltage by-products inherent in electronic circuits. The electromagnetic spectrum may be adversely affected, and the frequency band reserved for radio transmission may be damaged, without limiting the non-estimated electromagnetic radiation from electronic products. With the continuous explosion of the total number of non-wireless and radio products, the already crowded electromagnetic spectrum will become more crowded. Maintaining this key resource is particularly important to ensure that the equipment will continue to operate normally in the future.

2. Safety

For many products and industries, EMC performance may represent the difference between life and death. Many diagnostic and therapeutic, defense, industrial, aerospace and automotive products (as well as other products) have critical safety applications. If the function of these products is due to electromagnetic surge, ESD or radiated electric field and other electromagnetic conditions are invalid, then life will be in danger. Imagine that 300 mobile phones transmit 7 watts of power on a 36000 inch aircraft - this is a strict EMC test to ensure that the electrical system can withstand various electromagnetic environments.

3. Product performance (quality)

The function and performance of electronic products are vulnerable to external and internal influences. For example, if the internal power supply is adjusted too large, it will adversely affect the sensitive analog measurement (for sensor products), or reduce the performance of radio transmitters (for wireless products). This is an example of internal EMC challenges. From the external perspective, the application of EMC will have an adverse impact on the product in an almost endless way, from data destruction to measurement accuracy, and then from the performance IC after RF frying. EMC testing helps ensure that your machine is in a typical state. EMC runs again in the environment as expected, and (expected) reduces the return of products to the level of poor EMC performance.