Humidity, Moisture Sensors

The SHT21P is a humidity and temperature sensor designed for the professional market by Swiss-based Sensirion, providing high accuracy measurements in a wide range of temperatures. The sensor has a high degree of accuracy and high humidity resolution due to its measurement range of up to 0.01%RH and temperature accuracy up to 0.2°C in normal environmental conditions. The SHT21P is a robust and reliable humidity micro-transmitter with integrated temperature humidity sensor that is easy to install and operate.

Application Field

The SHT21P is ideally suited for a wide variety of applications such as environmental monitoring, HVAC control, industrial process control, building automation, scientific research, renewable energy systems, medical and consumer electronics. The sensor is also suitable for use in applications such as industrial production, clean room monitoring, and meteorological research. Due to the sensing element being laser trimmed, it has high linearity, hysteresis and temperature correlation.

Working Principle

The SHT21P uses capacitive sensor technology to measure humidity and temperature in the air. Its sensing element consists of two layers of polysilicon with a thin porous oxide spacer between them. The thin film is then exposed to the environment, allowing humidity molecules to pass through it and build up on the opposing layer, thus causing a change in capacitance. The change in capacitance is then measured using an electronic circuit, thereby providing an analog output that is converted to digital form.

The accuracy of the readings is improved by compensating for changes in temperature, humidity, and temperature-dependent effects. This is accomplished using a temperature-compensated humidity reference module that adjusts the measured values for extrinsic parameters such as air pressure and humidity, while an internal shutter determines the temperature coefficient. Additionally, the SHT21P has a wide temperature range and the capacitance rate of the temperature sensor is compensated in the reading process.

In addition to being highly accurate, the SHT21P is also low-power and low-weight, making it suitable for remote monitoring applications. Furthermore, it is ideal for portable measuring devices as it operates from a single 3-5V power supply. The SHT21P is also IP65 rated, meaning it is waterproof and dustproof.

The SHT21P is a reliable humidity and temperature sensor providing superior performance and accuracy in a wide range of applications. It is easy to install and simple to operate, making it the ideal choice for professionals looking for a reliable and accurate sensor for their projects.