The machine is made up of three main parts: measuring circuit of electric parameter, measuring circuit of photometric parameter and circuit of CPU system. Voltage and current signals are amplify and sent to high speed A/D transform, and the transform digital signals are sent to microprocessor, the input current signals of brightness detector are sent to A/D transform via I/V convert, and the transform digital signals are sent to microprocessor. Microprocessor processing the input photometric and electric data, it automatic switch between different range and calculate and display the data in the mean time.
