JPS61137228U

JPS61137228U -

Info

Publication number: JPS61137228U
Application number: JP2011185U
Authority: JP
Priority date: 1985-02-15
Filing date: 1985-02-15
Publication date: 1986-08-26

Description

[Brief explanation of the drawing]

第１図は従来の電磁流量計の励磁回路を示す構
成図、第２図は第１図に示す励磁回路の各部の波
形を示す波形図、第３図は本考案の一実施例を示
す構成図、第４図は第３図に示す実施例の各部の
波形を示す波形図である。１……電源、４，２１，３１……トランス、５
……トランジスタ、６ａ，６ｂ……整流平滑回路
、８，２３，３３……誤差増幅器、９……発振器
、１０……比較器、１１……駆動回路、１２ａ，
１２ｂ，１５ａ，１５ｂ……ダイオード、１４ａ
，１４ｂ……スイツチ、１３ａ，１３ｂ……コン
デンサ、２０，３０……電圧供給回路。 Fig. 1 is a configuration diagram showing an excitation circuit of a conventional electromagnetic flowmeter, Fig. 2 is a waveform diagram showing waveforms of each part of the excitation circuit shown in Fig. 1, and Fig. 3 is a configuration diagram showing an embodiment of the present invention. 4 are waveform diagrams showing waveforms at various parts of the embodiment shown in FIG. 3. 1... Power supply, 4, 21, 31... Transformer, 5
... Transistor, 6a, 6b ... Rectifier and smoothing circuit, 8, 23, 33 ... Error amplifier, 9 ... Oscillator, 10 ... Comparator, 11 ... Drive circuit, 12a,
12b, 15a, 15b...diode, 14a
, 14b... switch, 13a, 13b... capacitor, 20, 30... voltage supply circuit.

Claims

[Scope of utility model registration request]

a first rectifying and smoothing circuit that rectifies and smoothes the AC power source to obtain a positive DC voltage; a second rectifying and smoothing circuit that rectifies and smoothes the AC power source to obtain a negative DC voltage; and an output end of the first rectifying and smoothing circuit. a first capacitor connected to the output end of the second rectifying and smoothing circuit via a diode; and a second capacitor connected to the output end of the second rectifying and smoothing circuit via a diode.
a capacitor; means for connecting a series circuit of a first switch and an excitation coil of an electromagnetic flowmeter in parallel to the first capacitor; and a means for connecting a series circuit of a second switch and the excitation coil to the second capacitor in parallel. means, a diode connected in parallel to the first switch so that a current flows in a direction opposite to the excitation current flowing through the first switch, and an excitation current flowing through the second switch and in parallel with the second switch. a diode connected in a direction in which a current flows in a direction opposite to the current; and a first switch that supplies a voltage corresponding to the loss in the excitation circuit to the second capacitor after a predetermined time has elapsed after the first switch is turned off.
An excitation circuit for an electromagnetic flowmeter, comprising a voltage supply means and a second voltage supply means for supplying a voltage corresponding to the loss in the excitation circuit to the first capacitor after a predetermined time has elapsed after the second switch is turned off. .