PURPOSE: To measure humidity with simple circuit constitution and small average electric power consumption by converting the change in the electrostatic capacity of a humidity sensor to the form of a change in time constant and measuring the humidity intermittently.
CONSTITUTION: The rectangular pulses (a) generated in a pulse oscillating circuit 2 are applied to an integrating circuit 4 for comparison and an integrating circuit constituted of a humidity sensor 1 and a resistance R2. On the other hand, the pulse-like output signal (d) is fed to a max. signal amplitude value holding circuit 5 in order to maintain the max. amplitude value of the output signal (d) obtained with a differential amplifier 3 and to permit the indication of the max. amplitude value accurately even in the case in which the response time of a display device displaying the change in humidity or a recorder 8 is extremely long as cpmpared to the pulse widthof the output signal (d). The circuit 5 continues to output the output signal proportional to the max. value of the input signal.
| JPH058460 | [Name of device] Digital enthalpy meter |
| JPS6159252 | MEASUREMENT OF HUMIDITY |
KOUNO YOUZOU
KOTADO SETSUO
INAGAKI SHINTAROU
