Radiated noise

Noise can be broadly classified into normal mode noise and common mode noise, each of which is further divided into conducted noise and radiated noise. While conducted noise propagates along the power line, radiated noise is the noise emitted into the air from the power line. The main countermeasures against radiated noise are as follows.

1. Reduce the length of components or cables through which noise current flows.
2. Limit the noise current using resistance or inductance.
3. Place components or conductors that receive radiated noise at a distance from components or cables through which noise current flows.
4. Lower the frequency of the noise current.
5. Adopt a soft switching method.
6. Add a capacitor in parallel with the main switch.