PN结对交流信号相位的影响(续)

Influence of PN junction on phase change of AC signal(continued)

当1个交流小信号被1个PN结和1个大电容分压,且该电容的电容值远大于PN结电容时,大电容两端的电压与PN结电容成正比,该信号的相位与PN结的电阻以及信号的频率有关.把PN结当作1个电容和1个电阻并联,可定性解释该信号的相位与PN结正向电阻、与加在PN结两端的直流反向偏压、在零直流偏压下与交流信号频率的关系.

The voltage of AC signal is divided by a PN junction and a capacitor. When the capacitance of the capacitor is far greater than that of the PN junction, the output voltage of the capacitor is proportional to the capacitance of the PN junction, and the phase of the AC signal is related not only to the resistance of the PN junction but also to the frequency of the AC signal. If the PN junction is considered as parallel connection of a capacitor and a resistance, the relationships between the phase of the AC signal and the following variables can be interpreted qualitatively： the forward resistance of the PN junction, the backward DC voltage exerted on the PN junction, and the frequency of the AC signal when the backward DC voltage is zero.