PURPOSE: To measure humidity accurately with a simple unit, by holding a thermosensing element, which is heated at the open air temperature or more and has a temperature-resistance characteristic, in the open air and by detecting its resistance value change.
CONSTITUTION: A bridge circuit is formed with thermosensing element RS1 which is so held that it can be brought into contact with the open air, temperature compensating element RC1 which is held in absolutely dry state and is equivalent to element RS1, resistances R2 and R3, and variable resistance R4. A voltage is applied to the bridge circuit by power source E1 to make elements RS1 and RC1 into the self-heating stage (approximately 200°C), and the bridge unbalance output voltage appearing at both ends of load resistance R5 is adjusted to zero by variable resistance R4 while holding element RS1 in the atmosphere of relative humidity zero. Next, element RS1 is brought into contact with the open air to measure a generated unbalance output voltage, and simultaneously, the open air temperature is measured. Next, the relation between the bridge unbalance output voltage and the open air temperature with humidity as a parameter is utilized to obtain a value of humidity.
MIURA TETSUO
OOKUBO SHIYOU
NAGATA HIDEYUKI
| JPS369600Y1 |