Study On Transistor Characteristic Instrument Based On Virtual Instrument

Semiconductor is one of the most fundamental and important constituent of circuit in the electronic product. Without exaggeration, semiconductor establishes the foundation of the modern electronics. And the transistor as the fundamental constituent of semiconductor, engineers should regard how to use them rightly. In scientific research, engineers need the special instrument to test various transistors and use them properly according to the testing result.Virtual instrument is a system based on computer. It is not only provided with the basal function of traditional instrument but also a special and high performance-to-price ratio product. It is composed of computer, application software and instrument hardware. The computer hardware source combines instrument hardware with the software. That integrates the powerful data processing ability of computer with the testing and control function of instrument hardware. And with software, we can displays, storages and analyses the data.The paper briefly introduces the development of Virtual instrument and the software about LabVIEW. Then it introduces the buildup and working principle of the traditional transistor characteristic instrument. Then expatiates the data acquisition (DAQ) of virtual instrument and also introduces the structure and working principle of the NI 6024E DAQ card. Finally, the paper expatiates how to build this testing system with the software LabVIEW.The core of system is testing program with NI LabVIEW8.0.Which controls the instrument to finish all the testing tasks. And that includes the generation of all the needed scan signals for test , the acquisition about the voltage of test circuit node, the control of channels and work flow, the analysis about acquired data, the design of instrument panel, the display and storage of the test results and so on. The system hardware includes NI 6024E DAQ card, junction box, and testing circuit. The testing objects of the instrument are low power transistors, including the common diode, the bipolar transistor, the field effect transistor and so on. The instrument can get the different characteristic curves with different programs, using constructed virtual instrument system with the same hardware devices and wire connections. To have a convenience and multifunctional instrument, the subprograms can be united to form a main system. Finally the paper carries on the experiment about the transistor characteristic testing system and analyzes the testing results. The conclusion can be drawn that this testing system meets the intending requirements. This instrument is convenient, and has high precision, good expansibility and high cost performance. And which can meet the high precision testing requirement of the MOSFET threshold voltage.