What is EMI

What is EMI

EMI is the abbreviation of ElectroMagnetic Interference, which is a compound word, we should consider "electromagnetic" and "interference" separately.

The so-called "interference" refers to the two-layer meaning that the performance of the equipment is reduced after interference and the interference source that interferes with the equipment. The first layer of meanings such as thunder and lightning makes the radio produce noise, the motorcycle screen is driving around, snowflakes appear on the TV screen, and the radio sound is heard after picking up the phone. These can be referred to as "BC I" "TV I" "Tel I" , These abbreviations have the same "I" (interference) (BC: radio, TV: TV, Tel: telephone) followed by "electromagnetic". If the charge is static, it is called static electricity. When different potentials move in unison, an electrostatic discharge occurs, generating a current, and a magnetic field is generated around the current. If the direction and magnitude of the current continue to change continuously, electromagnetic waves are generated. Electricity exists in various states, we collectively call these states electromagnetic

What is an EMI filter

The EMI mentioned here is the English abbreviation of Electro Magnetic Interference. The literal translation is electromagnetic interference filter. It is a passive filter composed of inductance and capacitance. It allows the low-frequency useful signals to pass through smoothly, while suppressing high-frequency interference. This filter is a new type of component that has been popularized and applied in recent years. It can effectively suppress grid noise, improve the anti-interference ability of electronic equipment and the reliability of the system. It can be widely used in electronic measuring instruments, computer room equipment, switches Power supply, measurement and control system and other fields.

The feedthrough capacitor is a three-terminal capacitor, but compared with the ordinary three-terminal capacitor, because it is directly installed on the metal panel, its grounding inductance is smaller, and there is almost no influence of the lead inductance. In addition, its input and output The ends are isolated by a metal plate, eliminating high-frequency coupling. These two characteristics determine that the feedthrough capacitor has a filtering effect close to that of an ideal capacitor.