Abstract: Based on a fearture of decrease in the electrical resistivity of metabolite with bacteria propagating in culture medium, a microprocessor controled system is designed for automatic fast-becteria-detection on electrical impedance method. The system consists of five parts, maliny: bacteria-culture tubes, digit-controled stabiliger, microprocessor, A/D and D/A converters, printer and display screen, The system can determine impedance characteristic curves with bacteria propagation by a quadruyple electrodes method Within two to three hours. These impedance curves are used to identify whether there are common bacteria in a given sample, take drug sensibility tests and so on, In addition, the time for bacteria detection can be reduced very much and the detection efficiency becomes very high.

Key words: electrical impedance method, fast-bacteria-detection, quadruple electroues method, impedance characteristic curves