Alternating current (AC) impedance spectroscopy automatic testing device of positive temperature coefficient (PTC) thermistor

Abstract

The invention discloses an alternating current (AC) impedance spectroscopy automatic testing device of positive temperature coefficient (PTC) thermistor. The device comprises an electric heating oven for holding a sample, a temperature control and protection circuit for maintaining the electric heating oven at a constant temperature and preventing overcurrent, an impedance measuring circuit for measuring the sample impedance, and a master control machine connected with two circuits via a CAN bus respectively and used for receiving a user instruction and controlling the two circuits to accomplish measurement. The impedance measuring circuit in the invention is based on high-speed synchronous data acquisition and digital signal processing technology, satisfies the measurement requirements for high precision, wide measurement range and wide frequency band, and has features of small volume, low cost and convenient operation. Data communication among the temperature control and protection circuit, the impedance measuring circuit and the master control machine is realized via CAN buses, to achieve good real-time property and high reliability. The invention can ensure constant-temperature testing environment, carries out multi-frequency point scanning measurement to the AC impedance of the tested sample, and realizes full automatic testing of impedance-temperature characteristics of the PTC thermistor under different frequencies.

Description

technical field [0001] The invention belongs to the field of component parameter testing, in particular to a PTC thermistor AC impedance spectrum automatic testing device. Background technique [0002] Semiconducting BaTiO Doped with Trace Rare Earth Elements 3 The resistance value of ceramics is very low at room temperature, but as the temperature rises, a sudden change occurs near the Curie point, and the resistance value rises sharply, resulting in a significant PTC effect. Components made of this ceramic are called positive temperature coefficient (PTC) thermistors, and PTC thermistors are widely used in many fields such as household appliances, power facilities, electronic equipment, and the automotive industry. [0003] The resistance-temperature characteristic is one of the basic characteristics of the PTC thermistor, which refers to the relationship between the zero-power resistance value of the PTC thermistor and the temperature of the resistor body under the speci...

AI Technical Summary

Problems solved by technology

[0006] The object of the present invention is to provide an automatic test device for impedance-temperature characteristics of PTC thermistors at different frequencies, which solves the problems of unobjective characterization methods, poor usability of impedance measuring instruments, and low reliability of temperature control instruments in existing test equipment. , The communication interface of each discrete instrument is not uniform, etc., and can be widely used in the research, testing, characterization and evaluation of PTC thermistors, semiconductor ceramics, and various sensitive components.

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