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Study Of PTCR R-T Characteristics Measuring System Based On Single-chip Control

Posted on:2008-03-30Degree:MasterType:Thesis
Country:ChinaCandidate:S J WangFull Text:PDF
GTID:2178360272467125Subject:Microelectronics and Solid State Electronics
Abstract/Summary:PDF Full Text Request
The main performance characteristics of PTC(Positive Temperature Coefficient)thermal resistance (PTCR) contain R-T, V-I and thermal characteristic. Among these characteristics, R-T characteristic is the basic one. The determination of the properties of PTC materials is very important for their theoretical study and application. This dissertation gives a detailed discussion on the measuring principles and methods of PTCR's R-T characteristic. On the base of conventional R-T characteristic testing system which is based on the computer, FLUCK45 universal meter and temperature controller, and adjust the intelligence device'development of miniaturization and low cost, we design and develop PTCR R-T characteristic testing system which is based on the single-chip control and liquid crystal display.Testing system uses composite signal microcontroller C8051F020 single-chip as main controller, extends FLASH data storage device and liquid crystal display saving and displaying data.Testing system designs different ranges constant-current source, segmented and exactly measures out resistance which is between 0.1ohm and 600megohm, and combines single-chip control, realizes automatic switching of constant-current source ranges, replaces FLUCK45 universal meter measuring resistance module, and continues measuring resistance range from 300megohm to 600megohm. The system uses PCA of single-chip module creating a square pulse and serials in shift register, gates testing sample channels by way of optically coupled isolator and reversed module, saves single-chip port greatly. The system designs peripheral signal acquisition circuit of PT100 which transfers resistance change of PT100 as voltage change, afferents single-chip internal ADC0 module, pass through single-chip's disposal and control, and realizes temperature control .We test PTCR samples with designed hardware circuit and conventional R-T characteristic testing system, according to the testing result, we find that the R-T characteristic curve and R-T characteristic parameter got by the two testing method agree well, and confirm that the hardware circuit designed in this dissertation is feasible.
Keywords/Search Tags:PTC, C8051F020single-chip, constant-current source, liquid crystal display, FLASH data storage
PDF Full Text Request
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