Thermistor voltage effect test circuit and system

Abstract

The invention discloses a thermistor voltage effect test circuit and system, and belongs to the technical field of electronic circuits. The circuit comprises a pulse voltage source, a sampling resistor, two IGBTs, a single-chip microcomputer and a peak voltmeter. The pulse voltage source, the PTCR ceramic resistor to be tested and the sampling resistor form a series loop; one ends of the to-be-tested PTCR ceramic resistor and the sampling resistor are respectively connected with G poles of the two IGBTs, and the other ends of the to-be-tested PTCR ceramic resistor and the sampling resistor are respectively connected with a negative pole of the peak voltmeter; the positive electrode of the peak voltmeter is connected with the C electrodes of the two IGBTs. The single-chip microcomputer is respectively connected with E poles of the two IGBTs and is used for controlling on and off of the two IGBTs. The test system comprises a single chip microcomputer, a temperature control meter, an electric furnace, a computer and the circuit. According to the invention, the testing efficiency and precision of the thermistor voltage effect can be improved, the testing system is relatively simple, and the testing cost is low.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and more particularly, relates to a thermistor voltage effect test circuit and system. Background technique [0002] Barium titanate-based thermal ceramics have significant positive resistance temperature characteristics, that is, the Positive Temperature Coefficient effect (hereinafter referred to as the PTC effect). The resistance based on the PTC effect is a positive temperature coefficient thermistor, that is, Positive Temperature Coefficient of Resistance (hereinafter referred to as PTCR). At present, PTCR has been widely used in many fields such as communication, home appliances, transportation, etc., especially the rapid development of new energy vehicles. Big capital is competing for this new market, and PTCR is an indispensable electronic material in new energy vehicles. In addition to being used in automotive air conditioning equipment, it is also widely used in the engine ...

AI Technical Summary

Problems solved by technology

[0004] Existing voltage effect test systems for PTC thermistor ceramic resistors, such as the patented "PTC Thermistor Zero Power Voltage Effect Automatic Test System" (publication number: CN1477402A), use the direct measurement of the resistance of the PTCR, and the test port reads the measurement data The oscilloscope is used, the reading data is not direct, the speed is not fast enough, the channel switching speed is slow, and the efficiency is low; moreover, when measuring the current, the current fluctuates greatly and the reading accuracy is low; at the same time, the oscilloscope method is complicated to operate and the test system is relatively complicated. ; The isolation transformer made of self-winding coils uses an AC half-wave pulse voltage source, which is bulky and has low precision

More importantly, the output pulse is an AC half-wave, the voltage is not stable, and the output pulse is still relatively wide and lasts for a long time. When measuring, the PTCR resistor will still generate heat, so this method cannot be used in a real sense. zero power measurement

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