This document introduces how to build a system that measures relative humidity using LTC2991, which can achieve instrument-grade accuracy
The LTC2991 is designed for measuring supply voltages, currents, and temperatures on large circuit boards. It can achieve +1°C accuracy when used with an inexpensive MMBT3904 transistor as a temperature sensor, making it suitable for instrumentation applications requiring disposable sensors.
The document details a specific application where the LTC2991 is used to build a psychrometer. This setup uses two transistors (wet and dry bulb) connected to appropriate inputs of the LTC2991 to measure relative humidity based on temperature differences and atmospheric pressure.
The LTC2991 measures supply voltages, currents and temperatures on large circuit boards when used in system monitor applications.
Remote temperature measurements are guaranteed to be accurate to 1°C.