PURPOSE: To detect the flow direction, etc., of fluid in a fine space and a flow passage stably for a long period by constituting a detector so that the flow of the fluid can be detected electrically.
CONSTITUTION: When a source voltage is applied between an input terminal IN and GND, a heater H generates heat. When a positive characteristic thermistor is used as the heater, a temperature self-control function operates and stable heating value is obtained in correspondence to the source voltage. A resistance RL is a current limiting resistance and limits currents flowing through thermistors Th1 and Th2. If the fluid does not flow, the potential at an output terminal OUT 2 is a half as high as the voltage between an output terminal OUT 1 and GND on condition that the resistance values of the thermistors Th1 and Th2 are equal to each other. Further, when the fluid flows, the thermistor Th1 and Th2 vary in resistance value and, for example, when the fluid flows in the direction from the thermistor Th1 to the thermistor Th2, the temperature of the thermistor Th1 drops and the resistance value increases. Simultaneously, the temperature of the thermistor Th1 rises and the resistance value decreases. Consequently, the potential at the output terminal OUT 2 drops and the flowing direction of the fluid can be detected.
TAKAOKA YUICHI
YAMADA YOSHIHIRO
| JPS5796265A | 1982-06-15 | |||
| JP60179964B |