CONTROLLER FOR FLOW RATE

摘要

PURPOSE:To improve the accuracy of a titled controller by leading out both the ends of an electric heating resistor provided in a fluid through a filter circuit and controlling the flow rate by an output compared with a set value. CONSTITUTION:Current is flowed into a thermistor set in a fluid by a constant current circuit 19 and the voltage applied between both the ends of the thermistor 18 is inputted to a dividing circuit 21 provided with a thermistor 20. Voltage variation corresponding to the change of the velocity of flow and the flow rate is obtained in the output terminal 22 of the dividing circuit 21. The voltage is averaged by a filter circuit and then compared with a set value outputted from a set value outputting circuit 24 by a comparator 23. The flow rate is controlled by an output of the comparator 23.