公开(公告)号：US4683754A

公开(公告)日：1987-08-04

申请号：US857045

申请日：1986-04-29

申请人： Terutaka Hirata ,  Tadashi Azegami ,  Atsushi Kimura ,  Megumi Katayama

发明人： Terutaka Hirata ,  Tadashi Azegami ,  Atsushi Kimura ,  Megumi Katayama

IPC分类号： G01D5/24 ,  G01L9/00 ,  G01L9/12 ,  G01L19/04

CPC分类号： G01L9/0072 ,  G01L9/125

摘要： A capacitive displacement type transducer, wherein the oscillation frequency of a self-excited oscillator circuit including a pair of differential capacitors formed with a movable electrode disposed between two outer electrodes is counted by a counter, the output level of the counter is reversed each time a certain count is attained to cause the differential capacitances to be switched alternatively, and to make identical the respective reversal periods, and application voltage to be applied to the differential capacitors being controlled by an integrator, and a voltage relating to the output of the integrator being applied through a fixed impedance to the movable electrode, thereby eliminating fixed capacitances formed across the difference capacitors. Also, a voltage generated by dividing and averaging the output level of the counter by use of a certain pulse duration of a monostable circuit operating in synchronism with a counter, is used to compensate for static pressure changes. Also, a temperature sensing element is included in a converting section to perform temperature correction. The circuit may be used in a two wire transmission system. The circuit improves upon the prior art by eliminating heretofore used complex circuits, thereby increasing reliability, efficiency and reducing size.

摘要翻译： 一种电容式位移式换能器，其中包括由设置在两个外部电极之间的可动电极形成的一对差动电容器的自激振荡器电路的振荡频率由计数器计数，每次计数器的输出电平反转 达到某些计数以使差分电容被交替切换，并使各个反转周期相同，并且施加到由积分器控制的差分电容器的施加电压，并且与积分器的输出相关的电压为 通过固定阻抗施加到可动电极，从而消除形成在差分电容器两端的固定电容。 而且，使用通过使用与计数器同步运行的单稳态电路的特定脉冲持续时间对计数器的输出电平进行分频和平均而产生的电压来补偿静态压力变化。 此外，温度感测元件包括在转换部分中以执行温度校正。 该电路可用于双线传输系统中。 该电路通过消除以前使用的复杂电路来改进现有技术，从而提高可靠性，效率和减小尺寸。