Circuit for weakening excitation current peak, electromagnetic flowmeter and electronic device

Abstract

The invention provides a circuit for weakening an excitation current peak, an electromagnetic flowmeter and an electronic device. The circuit comprises a constant-current generator circuit, a loading circuit and a conduction delay circuit, wherein the output end of the constant-current generator circuit is electrically connected with the input end of the loading circuit; the output end of the conduction delay circuit is electrically connected with the input end of the constant-current generator circuit. The circuit for weakening the excitation current peak has the advantages that a delay loop consisting of a second resistor R2 and a capacitor C is used for controlling the conduction degree of a transistor Q in 1ms before an excitation cycle, so that the current peak in 1ms before the excitation cycle is well weakened, and the influence to the normal excitation current after 4ms is avoided; the structure of the whole circuit is simple, the cost is low, the efficiency is high, and the practicality is strong.

Description

technical field [0001] The invention relates to the field of excitation circuits, in particular to a circuit, an electromagnetic flowmeter and an electronic device for weakening excitation current spikes. Background technique [0002] The electromagnetic flowmeter excitation circuit constructed with LM317 as the core is an open-loop control system, which has poor stability due to no negative feedback. During the experimental test, it was found that in the constant current generator of the excitation circuit constructed by LM317, a huge current spike will be generated within 1ms before each excitation cycle, and this current spike will cause certain physical damage to the excitation circuit, reducing the The reliability of the excitation circuit is improved. SUMMARY OF THE INVENTION [0003] In view of the above technical problems, the present invention provides a circuit, an electromagnetic flowmeter and an electronic device for weakening the excitation current peak, whic...

AI Technical Summary

Problems solved by technology

[0002] The excitation circuit of the electromagnetic flowmeter built with LM317 as the core is an open-loop control system, because there is no negative feedback, so the stability is poor

During the experimental test, it was found that in the excitation circuit constant current generator built by LM317, a very large current peak will be generated within 1 ms before each excitation cycle, which will cause certain physical damage to the excitation circuit and reduce the The reliability of the excitation circuit

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