Common-mode inductor resistor filter circuit 2

When the ∞ value is constant, the larger R and C2, the smaller the ripple coefficient, which means the better the filtering effect. As R increases, the DC voltage drop across the resistor will also increase, thereby increasing the internal losses of the DC power supply; If the capacitance of C2 is increased, it will also increase the volume and weight of the capacitor, which is not practical to implement. This type of circuit is generally used in situations where the load current is relatively small. 2. Inductive filtering circuit is composed of capacitor C and inductor F according to the different impedance of reactive components for AC and DC. The basic form of the filtering circuit is that capacitor C is open to DC and has a small impedance for AC, so it is connected in parallel at both ends of the load. Inductor L has a small DC impedance and a large AC impedance, so it should be connected in series with the load. 4. EMI filter is adiode commonly used filter for power supply EMI filters. The power supply filter has two input terminals, two output terminals, and one ground terminal. When in use, the housing should be connected to the ground. The circuit includes a common mode choke coil (also known as a common mode inductor) L and filtering capacitors Cl~C40L, which do not work against series mode interference. However, when common mode interference occurs, due to the same magnetic flux direction of the two coils, the total inductance increases rapidly after coupling, resulting in a large inductive impedance to the common mode signal, making it difficult for it to pass through. Therefore, it is called a common mode choke coil. Its two coils are wound around ferrite magnetic rings with low loss and high permeability. When current passes through, the magnetic fields on the two coils will strengthen each other. The inductance of O L is related to the rated current of the EMI filter.diode