研究近年来的高考试题,发现光电效应管中光电流与电压之间的关系是一个常考知识点,能很好的体现学生的综合分析能力.原理:金属制成的阴极在光的照射下放出光电子;如果阴阳两极上加如图所示的正向电压时,电子就会加速到达阳极A,在入射光一定时,增大光电管两极的正向电压,单位时间到达阳极的光电子数目就会增加,光电流会随之增大;但是随着电压的增加光电流不会无限增大,要受到光电子数量的约束,有一个最大值,这个值就是饱和电流Im,当电压再增大时光电 Study of college entrance examination papers in recent years, found that the relationship between photocurrent and voltage in the photoelectric effect tube is a common knowledge, can reflect the students’ comprehensive analysis ability. Principle: the cathode made of metal under light irradiation Emits the photoelectron; If the positive and negative poles as shown in the figure plus the forward voltage, the electron will accelerate to reach the anode A, when the incident light is certain, increase the photocurrent of the bipolar forward voltage, the unit of time to reach the anode photoelectrons on Will increase, the photocurrent will increase; but with the voltage increase photocurrent will not increase indefinitely, to be subject to the number of optoelectronic constraints, there is a maximum, this value is the saturation current Im, when the voltage increases photoelectric