The Measurement System Design of the Liquid Viscous Coefficient

The measurement accuracy of the common measurement system is very low due to the stopwatch by hand, the parallax and the ball by the falling off center. In the research, the measurement system included SCM, the corresponding circuit and interfaces of laser emission and receiving, which can overcome the parallax and reaction speed, and the measurement error of the falling ball will reduce, and the measurement system will guide the students to grasp a new kind of timing measurement, speed measurement and counting methods. The hardware circuit of the system included the power, the SCM (AT89C52), digital display circuit, laser tube, photosensitive diode and related circuit, etc. The diagram of the measurement system software of the liquid viscous coefficient included the initialization, the upper laser block, the below laser block, timer start, timer off, time and number save, key-press treating and display, etc. This research not only preserves original experiment device operation and experiment content, and adds the laser photoelectric timer principle and usage, the knowledge aspect will expand, and the accuracy of measurement and the experimental teaching of modernization will improve. The results show that the relative error of castor oil viscous coefficient (14°C) is only 1.3% by the measurement system, the measurement precision was greatly improved, and the research will provide the ideas and methods for the viscous coefficient measurement and the timer design.