The Development of Sensitive Measuring Schemes for Capacitive-Semiconductor Humidity Transmitters

Abstract

Capacitive-semiconductor converters play a crucial role in converting physical quantities with complex parameters due to their positive properties, including measurement accuracy, reliability, manufacturability, and efficient measurement schemes. Experimental results and discussions reveal that at small and medium humidity values (2÷6%), the bridge measuring circuit may not provide the necessary gradation and sensitivity of the output signal. To address this, a measuring circuit is developed to increase sensitivity and linearize the output characteristics of the capacitive-semiconductor converter at low and medium humidity values. The proposed measuring circuit utilizes a bipolar voltage for input value modulation, introducing a new construction principle for capacitive-semiconductor humidity converters. The measuring scheme enhances the accuracy and linearity of static characteristics by utilizing bipolar pulses of varying durations. The study establishes the practical value of pulsed power supply, providing additional opportunities for linearization of conversion characteristics. The presented results contribute to the development of effective measuring circuits for capacitive-semiconductor converters, enhancing their metrological characteristics and widening their applications in monitoring and control systems.

Keywords

• measuring circuit
• humidity
• capacitive-semiconductor converter
• accuracy
• bipolar voltage
• pulse duration