A new network model of electronic smoothing filter is proposed and it is proved that this model has a ideal smoothing factor approaching infinity theoretically. In the experimental circuits

both the reverse-connected composite mode of transistor and the positive grid characteristics of vacuum-tube are used. Therefore

the filtering function of the electronic devices is performed to the fullest.The results of experiments show that

the smoothing factor of transistor filter may reach 11000 and the smoothing factor of vacuum-tube filter may reach 2300.