What electromagnetic interference does the power adapter generate during operation?

Power adapters may generate the following types of electromagnetic interference during operation:
1. Conducted interference Differential mode interference: Cause of generation: Mainly caused by high-order harmonic currents generated by nonlinear components such as switching tubes and rectifier diodes inside the power adapter during operation. These high-order harmonic currents are conducted to the power grid in the form of differential mode (i.e., between the phase line and the neutral line), causing interference to other electronic devices. Impact manifestation: May lead to problems such as unstable operation, data errors, and increased noise in other sensitive devices connected to the same power grid. For example, when nearby audio equipment is subject to differential mode interference, a buzzing noise may occur. Common mode interference: Cause of generation: Usually due to the presence of distributed capacitance between the power adapter and the ground, as well as parasitic capacitance of the internal circuit and other factors, causing high-order harmonic currents to be conducted to the power grid in the common mode form (i.e., between the phase line and the ground wire, and between the neutral line and the ground wire). Impact manifestation: Common mode interference may affect the normal operation of various electronic devices connected to the power grid, especially having a more serious impact on those devices with high input impedance. For example, common mode interference may cause failures in computer network communications, resulting in data transmission errors or interruptions.

2. Radiated interference Near-field radiation: Cause of generation: The high-frequency switching circuit inside the power adapter will generate rapidly changing electric and magnetic fields during operation, and these electric and magnetic fields will generate near-field radiation in the surrounding space. In addition, components such as power cords and transformers may also become radiation sources. Impact manifestation: Near-field radiation may interfere with nearby electronic devices, especially those devices using wireless communication such as Bluetooth devices and wireless mice. For example, near-field radiation may cause unstable connections of Bluetooth devices, with disconnections or weak signals. Far-field radiation: Cause of generation: When the high-frequency signals inside the power adapter radiate outward through components such as power cords and radiators, far-field radiation will be formed. The intensity of far-field radiation is related to factors such as frequency and power. Impact manifestation: Far-field radiation may interfere with other electronic devices and radio communication systems in the surrounding environment. For example, in places with high requirements for the electromagnetic environment, such as hospitals and airports, the far-field radiation of power adapters may affect the normal operation of medical equipment or aviation communication equipment.