HEAT RESISTANCE TYPE AIR FLOWMETER

摘要

PROBLEM TO BE SOLVED: To provide a heat resistance type air flowmeter capable of easily measuring a bidirectional flow rate and having proper sensitivity characteristics. SOLUTION: The temperature of a heating resistor Rh is controlled by an operational amplifier OP1 so as to obtain a constant temperature difference with respect to the temperature of air and temperature sensitive resistors Ru, Rd are arranged on the upstream and downstream sides of the heating resistor Rh. The control voltage of the heating resistor Rh is supplied to the temperature sensitive resistors Ru, Rd connected in series through the operational amplifier OP1. The flow velocity of air is measured based on the contact potential of the temperature sensitive resistors Ru, Rd connected in series.