Linear voltage-controlled resistor for temperature difference control of constant temperature difference thermal film flowmeter

The invention discloses a linear voltage-controlled resistor for temperature difference control of a constant temperature difference thermal film flowmeter, and belongs to the field of flowmeter design. The circuit structure disclosed by the invention comprises a voltage follower (1), a reference resistor (2), a proportional amplifier (3), an analog division circuit (4) and a subtractor (5), the input end of the proportional amplifier (3) is connected with PORT1 end voltage Ui, and the in-phase input end of the subtractor (5) is also connected to the voltage Ui. According to the voltage-controlled resistance circuit, a resistance simulation circuit with the resistance value linearly changing along with the voltage is provided, and the equivalent resistance value between the input end of the PORT1 and the ground end of the PORT2 can be linearly adjusted through the external control voltage Uc. The automatic temperature difference control circuit is high in precision, simple in circuit structure, stable, reliab