几乎所有设备的传导干扰都包含共模噪音和差模噪音，开关电源也不例外。共模干扰是由于载流导体与大地之间的电位差产生的，其特点是两条线上的杂讯电压是同电位同向的；而差模干扰则是由于载流导体之间的电位差产生的，其特点是两条线上的杂讯电压是同电位反向的。-almost all the equipment includes EMI common mode noise and differential mode noise, switching power supply is no exception. Common mode noise is due to current carrying conductor between the earth and the potential of the poor, Its characteristics are two lines of noise voltage is the same with the potential to; while differential mode interference is the result of current-carrying conductor of the potential difference, Its characteristics are two lines of noise voltage potential is the reverse of the same.