The small resistance tester based on C8051F005 one-chip computer is designed

We have adopted the one-chip computer, utilize the advantage of the one-chip computer to design this survey meter. This survey meter can read out the resistance quantity measured from LCD display screen directly, the measurement limit is 10 2. 9999k, can store the data tested at the same time, then is sent into the upper computer by the serial port, pass the strong
The small resistance tester based on C8051F005 one-chip computer is designed - schematic

function of the upper computer, can analyze, deal with the data measured. The survey accuracy of this tester is up to 0. 1%, and adopt the tetrapolar measurement method, resistance quantity is not influenced by the lead wire size and contact resistance. Not only it is simple and convenient to measure, reading is ocular, and the survey accuracy, definition are also higher than the general electrical bridge. It can be used for the laboratory, research institute, is especially suitable for the working site. It pursues local basic principles to be to adopt in examine at the resistance through the known constant current as above, take out the pressure drop on the resistance examined, amplify and change into 0- 3V direct-current volts by the amplifier, then send into the input terminus that C8051F005A/D changes, deal with the one-chip computer, pass the liquid crystal display direct display electric resistance value finally. Because of realizing the measurement of the minification resistance, require the definition of the amplifier to be high climax reach 10 V, The linear scale is good, input impedance is high, and demand to drift about low, noise suppression and antijamming capability are strong, we have designed the difference amplifier as signal processing circuit in Fig. 2 shows for this. This amplifier is made up of operational amplifier A1, A2 in fractional circuit of first difference, A3 makes up the fractional circuit of...

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