Abstract:  A physics experiment teaching system constructed by using general purpose instruments can improve the freedom of equipment usage, highlight physical principles behind the experimental measurements, assist students in better experiment experiences with scientific research thinking, and improve the quality of innovation training. A photoelectric effect experiment system based on LabVIEW platform is designed, which uses fA-grade high-precision electrometer transimpedance amplifier to detect photocurrent and uses NI myDAQ to collect data. With this system, quantitative real-time record can be completed. Visual display the variation of photocurrent IKA with anode voltage UKA，multiple IKA-UKA characteristic curves with different parameters are displayed in the same coordinate. The cut-off voltage U0 of different spectra lines (frequency ν) is measured. The U0-ν fitting curve and Planck constant h are obtained by data analysis module. The system is used to measure a set of spectral lines, get h=(6.63±0.28)×10-34 Js. It is consistent with the recognized value h0=6.62606896×10-34  Js,  and the relative error is about 0.40%. The results show that the measured results of the system agree well with the recognized value of Planck constant.

Key words: photoelectric effect, Plank constant, NI myDAQ, LabVIEW