The high capability of relay is required , otherwise , the reliability of the wholly system in which the relays are used is fall , even some fates may be bring 继电器作为典型的控制元件，广泛地应用于各种控制系统中，为了这些系统的可靠性与安全性，要求其具有较高的性能。
If such additional devices as are added , recording mechanism , and electric mapping device , then recording , remote transmission , alert , automatic control , etc . will be realized 若增加附加装置，如记录机构、电气变换装置、控制元件等，则能实现压力的记录、远传、报警、自动控制等。
Hydraulic flapper - nozzle servo - valve is the most important component in hydraulic control systems . it is used very widely in industrial and aerospace application fields because of its high responding speed 喷嘴挡板伺服阀作为伺服控制元件,是闭环电液伺服控制系统中最重要的核心元件。
Their structures and principle were narrated in details and at the same time , the new actuators used in electric - pneumatic proportion / servo valve in the future were presented 对现有电气比例伺服控制阀的结构及工作原理作了简单的叙述，结合新型驱动方法阐述了未来电气比例伺服控制元件的发展。
The developments of this digital synchronous valve and the application to hydraulic synchronous system can be founded on these results . and it is ready for the perfection of the digital valve 本文的工作为该数字同步阀的研究及其应用打下了一定的基础，也为后续的数字阀为控制元件的产品完善作了前期准备。
Jl electronic co . , ltd . is an enterprise engaged in the production of automation control components such as photoelectric switch and mark sensor . the products passed the provincial certification in 1988 健埃尔电子有限公司是专业生产光电开关，标志传感器等自动化控制元件的科技型企业，公司产品于1988年通过省级鉴定。
These valves are one kind of controllers which control pressure or flow rate continuously vary in proportion with electric input signal . they are typical mechanical , electrical and hydraulic integral products 比例阀所控制的压力或流量，是随输入电信号大小而成比例的，连续变化的控制元件，是典型的机-电-液-一体化产品。
If the response is unsatisfactory and modification of the plant is unacceptable , a design phase is necessary to select the control elements ( the controller ) needed to improve the dynamic performance to acceptable levels 如果响应不满意且不能改变对象，则需要第二阶段：选择控制元件（控制器）以将性能指标改进至可接受的水平。
As a kind of typical controlling apparatus , the relay is widely used in many control systems . the high performance of relay will be claimed lest the reliability of the entire system employing the relay is on the decline 继电器作为典型的控制元件，广泛地应用于各种控制系统中，为了这些系统的可靠性与安全性，要求具有较高的性能。
Vacuum breaker is widely applied in the reactive power compensation as the switch of shunt capacitor banks , which will cause reignition and over - voltage after the switching performance gets deteriorated 进行无功补偿时广泛使用真空断路器作为并联电容器组的开关控制元件,其操作性能劣化后,突出的表现就是极易发生重燃和操作过电压危害。
