humidity detection device

Abstract

Abstract PURPOSE:To obtain a detector which produce a wide ranging frequency output and a sine wave output with limited distortion, by arranging a Wien bridge type oscillation circuit having two electric resistance type moisture sensors. CONSTITUTION:A moisture detection circuit comprises a difference input amplifier 1, capacitors 6 and 7, two electric resistance type moisture sensors 8 and 9 made of the same moisture sensing material for determining oscillation frequency and the like which form a Wien bridge type oscillation circuit. For example, the two sensors 8 and 9 are formed on the same substrate to vary the oscillation frequency by changing the resistance values of the sensors 8 and 9. Thus, a wide ranging frequency output and a sine wave output with limited distortion can be obtained regardless of about three-digit exponentially functional changes in the resistance values of the sensors 8 and 9 due to moisture and changes therein due to temperature and can be inputted direct into a microcomputer.

Inventors

• 👤 Shigeki Tsuchiya
• 👤 茂樹 土谷
• 👤 Hiroji Kawakami
• 👤 寛児 川上
• 👤 Toru Sugawara
• 👤 徹 菅原
• 👤 Teruo Tsunoda
• 👤 角田　照夫

Bibliographic Details