1 is different. The photocurrent curve of the anode is the photoelectron released by the anode being polluted by the cathode material under illumination, and its direction is from the anode to the cathode, while the normal photocurrent is from the cathode to the anode. Therefore, when a reverse voltage lower than the cut-off voltage is applied to the photocell, the cathode photocurrent is cut off by this voltage, and the anode current accelerates, so we can see a basic negative photocurrent curve in the interval where the reverse voltage is lower than the cut-off voltage (generally, the instrument will take the cathode current as the positive direction), which is caused by the anode current. In the interval above the cut-off voltage, the cathode current begins to appear, and the anode current will be dispersed due to the decrease of the acceleration voltage, which leads to the gradual decrease of the anode current at this time (that is, the anode current curve forms a curve from a straight line up). When we apply DC voltage to the photovoltaic cell, the cathode current will be accelerated by DC voltage, and with the increase of voltage, the cathode current will gradually change from scattering to DC. When all electrons are accelerated by the accelerating voltage to the electrons that can contact the anode, the cathode current will enter the saturation section, and the anode current will be cut off by the DC voltage and become zero.

The others didn't arrive at Baidu. . tragedy

I did the experiment last semester. .