Hot wire current limiting protection circuit of hot wire anemometer

Abstract

The invention discloses a hot wire current limiting protection circuit for a hot-wire anemometer, which comprises a current sampling resistor, a differential signal amplifier, a comparator, a D-type trigger, a switching and indicating circuit, a current limiting protection self detection switching circuit, a hot wire analog resistor and a current limiting protection management module, wherein the differential signal amplifier amplified a potential difference signal generated by hot wire working current flowing through the current sampling resistor, a voltage signal reflecting the hot wire working current is obtained, threshold voltage provided by the current limiting protection management module is compared via the comparator, a protection signal is generated, the protection state is locked via the D-type trigger, a hot wire loop is further controlled to be cut off, a current limiting protection role is played, and in addition, a self detection function is provided for the current limiting protection circuit. The hot wire current limiting protection circuit for the hot-wire anemometer has the advantages that current limiting protection is accurate, timely and reliable, and the hot wire can be prevented from being burnt down by over large hot wire current.

Description

technical field [0001] The invention relates to the technical field of electronic measurement, in particular to a hot wire current limiting protection circuit of a hot wire anemometer. Background technique [0002] The hot wire anemometer is widely used in the measurement of fluid flow velocity. Its working principle is to place the hot wire in the fluid, heat the hot wire through the circuit current, and at the same time conduct heat exchange between the hot wire and the fluid. Through the balance between heating and heat dissipation, the flow velocity The signal is converted into an electrical signal to realize the measurement of the flow rate. Therefore, the hot wire is the key sensitive element of the hot wire anemometer measurement system. In order to improve the sensitivity of flow velocity measurement, the hot wire of the hot wire anemometer generally uses a thin-diameter tungsten wire with a relatively large resistance temperature coefficient. The heat capacity of th...

AI Technical Summary

Problems solved by technology

Therefore, the hot wire is the key sensitive element of the hot wire anemometer measurement system. In order to improve the sensitivity of flow velocity measurement, the hot wire of the hot wire anemometer generally uses a thin-diameter tungsten wire with a relatively large resistance temperature coefficient. The heat capacity of the thin tungsten wire is small. If the working current is not set properly or the wiring is improperly connected and other misoperations occur, the current flowing through the hot wire will often exceed the allowable value, resulting in the hot wire being blown.

At present, the protection of the hot wire of the hot wire anemometer is generally based on the user's operating experience, and there is a lack of current limiting protection measures.

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