humidity sensor

7-72 — elektor July/august 1981 1 14 C8 10 ,L :16 V• Tent. 31 to Ilk i4 humidity 7 Encouraged by the enormous response to the publication of the humidity sensor in April 1981 issue of Elektor, our designers decided to prepare a slightly modified circuit. This also allowed the possibility of altering the power supply slightly so that temperature changes no longer affect the results. This can be realized by using the well-known voltage regulator IC, the 723, which happily combines a very high specification and a low price. Further, its lack of sensitivity to temperature changes is excellent. To obtain an output voltage of 6.5 V, the 723 must be provided with a supply voltage that does not fall below 9 V. April 1981 issue, which also described its operation we shall include and calibration. Just as The a brief summary here. The Valvo humiditY sensor "higdghe"telonger than voltage. To obtain a reliable reading the entire should really be seen as a capacitor, consisting of a separa...