EMD-4000B Humidity Sensor The EMD-4000B is a bulk resistance-type humidity Features sensor based on the impedance change of a thin- film polymer due to water vapor absorption. The Excellent interchangeability polymer is deposited on Bismuth alloy terminals, which are set on a ceramic substrate. The sensor Standard Accuracy 5% is excited by a low voltage alternating current and the impedance measured as a function of relative Economical humidity. Recovers from condensation The thin-film polymer consists of chemical functional groups that disassociate into ionic Good resistance to chemical vapors species as water vapor is absorbed. This results in increased electrical conductance through Fast response the sensor or a decrease in impedance. The impedance is an inverse exponential function of Low hysteresis the surrounding humidity. Amphenol Advanced SensorsThe EMD-4000B is capable of withstanding Manufacturers (OEMs) with requirements to incorporate environments where organic vapors are present. It humidity sensors in HVAC controls, data loggers, recovers from condensing environments and may be appliances, automotive applications and consumer used at temperatures up to 185F (85C). The EMD- products. 4000B is also capable of in situ measurement of soluble water in organic liquids such as transformer oil, gasoline, toluene, acetone, and other compounds of varying hydrogen bond strengths. The EMD-4000B is highly repeatable and interchangeable. The sensor is manufactured in high yields to 5% RH or better tolerances. This results in a sensor that can be used in many designs without the need for humidity calibration, where the measuring circuit can be calibrated with external reference resistors. The EMD-4000B exhibits a well defined standard response curve as a function of humidity and temperature and has low hysteresis and fast response. The EMD-4000B is priced for Original Equipment Response Curves EMD4000 (1 VAC, 1 kHz) 1.00E+07 1.00E+06 5C 1.00E+05 15C 25C 35C 1.00E+04 45C 1.00E+03 1.00E+02 10 20 30 40 50 60 70 80 90 RH% Impedance (ohms)