SMARTEC Humidity sensor : SMTHS10 / SM240-15B01
Preliminary Specifications:
MOST IMPORTANT FEATURES TYPICAL APPLICATIONS * Linear 0 - 100 % RH * Airconditioners * High Performance * Climate control for green houses * Long Term Stability * Storage and warehouses * Close tolerances * Meteorological applications * Reliable construction * Food processing and * Room comfort control * Very low cost * Medical applications * and many more
PRODUCT HIGHLIGHTS
The Smartec capacitance humidity sensor measures from 0 to 100 % RH. In many applications 100 % RH and condensation may occur. This condensation has no effect on the performance of the Smartec humidity sensor.
Linearity. The Smartec humidity sensors has a linear capacitance change from 0 % to 100% RH within a band of 2%.
Due to this and the production technology on silicon substrate we can offer now a humidity sensor at a price level that will allow measurement of humidity where the traditional humidity sensors are to expensive or to unreliable.
Due to its robust construction the response time is a little slower as should be. Therefor we do not recommend the use of the sensor for applications where a very high speed of response is required.
PRODUCT DESCRIPTION
The Smartec humidity sensor is a two terminal capacitor which increase in value as water molecules are absorbed into its active polymer dielectric. The capacitor plates consists of a base plate and a water permeable platinum top plate. The sensor will be delivered with gold-plated lead wires attached. Besides the active dielectric, polymers give protection to the base plate, prevent polarisation and pinholing and generally ruggedise the sensor so that it can be used in a wide range of hostile environments
| SPECIFICATION | |
| Electrical: | |
| Operating humidity range | 0 - 100 %RH noncondensing |
| Operating temperature range | -40 – 120 șC |
| Capacitance value @ 25 șC, 60 %RH, 100 KC | 240 pF ±15 % |
| Capacitance range over 0-100 % RH | 40 pF ±10 % |
| Advised frequency range | 10-100 Kc |
| Temperature dependency | -0.15% RH/șC |
| Response time top 90 % | 60 s. typ. |
| Linearity | ± 2% RH |
| Stability over time(12 month) | ± 3 % RH |
| Maximum Voltage(no DC!) | 5 V AC |
| Storage | |
| Humidity range | 0 – 100 %RH |
| Temperature | -20 – 85 șC |
The measuring of humidity is difficult. Generally the humidity in air is measured as the fraction of the maximum amount of water that air can absorbed at a certain temperature. At atmospheric conditions and a given temperature this fraction can vary between 0 (absolute dry) and 100% (the point where condensation will begin to form). This relative humidity is only valid at a certain temperature and atmospheric pressure. Therefor it is important that a humidity sensor should not be affected by either temperature or pressure. Many sensing techniques, such as mechanical devices and resistive type sensors are temperature dependent and even the wet and dry bulb is pressure dependent.UNDERSTANDING THE SPECIFICATIONS
TOLERANCE.
The specified tolerance is the tolerance of the capacitor at 60% RH. This tolerance can be considered as an effect of the production technology. When the capacitor is f.i. 2 % to high (@ 0% RH) also the sensitivity will be around 2% to high.
LINEARITY.
The linearity is considered as the maximum deviation from a straight line between 0% RH and 100% RH. In the condensing area some drift can be expected; but this drift is reversible. The device is resistant against submerge in water.
PACKAGE OUTLINE AND SOLDERING PRECAUTIONS.
Soldering.
The products is special suited for soldering by hand. Special precautions has to be taken:
- a heat dissipater(pincers) has to be placed between pins during operation,
- soldering temperature must be below 350 C
- soldering time must be below 3 seconds.Outline drawing
Humidity Sensor type SMTHS10 All sizes in mm
Leads : gold pleated, Thickness 0.4 mm
Rev. January 23, 2001 |
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