Patent ID: 6047597
Filing Date: 2000-04-11
Classification: G01D,G01F

Abstract:
A device for determining the throughput of a flowing medium, having a substrate, which can be exposed to the flowing medium, on which a first resistor arrangement (R1, R2, R3, R5, RH, RHF), which is a component of a heat control circuit, is arranged, with at least one resistor RH, which is heatable to a predeterminable temperature, and a second resistor arrangement (RAB1, RAB2, RAU1, RAU2), which is wired as a bridge, whose one diagonal is located between a supply voltage and ground and includes at least two temperature-dependent resistors (RAB1, 2, RAU1, 2) which, in relation to the flow direction of the flowing medium to be detected, are arranged above and below the heater resistor (RH), so that they are evenly heated by it, while they are being cooled at different rates by the flowing medium, and the measuring voltage (UM) which occurs as a result of the temperature difference is evaluated at the other bridge diagonal for determining the throughput, characterized in that a third resistor arrangement (HTA) is provided, which comprises resistors (R11, R12,) temperature-dependent resistors (R15, R16) in a bridge circuit and at least two potentiometers (P2, P3), which are located in the transverse arm of the bridge, and which detects a diagonal voltage, which is a function of the temperature and is superimposed by the measuring voltage.