5-4. Summary of Chapter 5
Chapter 5 has described conductor conduction and common mode. This chapter has presented relatively precise explanations for common mode noise, mechanism of its occurrence, and means for prevention.
Fig. 5-4-1 Relationship of topics
In terms of noise emission problems of electronic devices, it is very difficult to take measures for common mode noise. Electronic devices are designed to make the loop area of circuit current as small as possible so that the wiring does not work as an antenna for noise. Although it is effective for the normal mode current, it is not so effective of the common mode current.
In addition, the common mode noise often flows via floating electrostatic capacitance. It is hard to figure out this capacitance (due to dependence on cable layout) and is difficult to design as a circuit. Furthermore, if common mode noise occurs somewhere in a circuit, the entire system is contaminated via the ground. Such a characteristic is making it difficult to take measures for common mode noise.
Common mode noise often occurs from incomplete grounding. It is effective to enforce grounding for reducing common mode noise. Common mode choke coil is effective as an EMC measure component.
Fig. 5-4-2 Summary of Chapter 5
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Noise Reduction Techniques in Electronic Systems Second Edition
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