System Monitor with Instrumentation-Grade Accuracy Used to Measure Relative Humidity

摘要

Because much can be deduced about a physical system by measuring temperature, it is by far the most electronically measured physical parameter. Selecting a temperature sensor involves balancing accuracy requirements, durability, cost and compatibility with the measured medium. For instance, because of its low cost, a small-signal transistor such as the MMBT3904 is an attractive choice for high volume or disposable sensing applications. Although such sensors are relatively simple, accurate temperature measurement requires sophisticated circuitry to cancel such effects as series resistance.