交流电压

When the cables use in alternating current system, rated voltage of cables should be at least equal the rated voltage of the system; When the cables use in direct current system,rated voltage should be not greater than 1.5 times of the rated voltage of the cables .

当电缆使用于交流系统时，电缆的额定电压至少应等于该系统的额定电压；当电缆使用地直流系统时，该系统的额定电压应不大于电缆额定电压的1.5倍。

Overvoltages are initially clipped by breakdown clamping until the voltage rises to the breakover level, which causes the devices to crowbar into a low-voltage on state.

保护器由一个匀称电压触发型双向交流二极管组成，过电压最初被弱钳位剪除址到电压上升至超过的级别，该级别会造成装置进入一个低电压开启状态。

This system is designed based on SPCE 061A microcontroller to measure the close loop parameters of the amplifier. The system can measure the input offset voltage、the input offset current、the open loop AC differential mode voltage gain、the AC common mode rejection ratio and unit gain bandwidth,using the measure method of assistant amplifier. What is more, data printing is completed in this system.

摘要本系统是基于SPCE 061A 单片机的运算放大器闭环参数测试系统，该系统采用辅助运放测试方法，可对运放的输入失调电压、输入失调电流、交流差模开环电压增益和交流共模抑制比以及单位增益带宽进行测量，并具有将测试数据打印输出的功能。

Starting from the steady-state performance of three-phase fully-controlled rectified circuit, which is with large inductive load, we take the front two items of the Maclaurin series of the DC voltage average as approximate formula, with considering of the effect of the AC-side inductance first, and further effect of AC resistance on DC voltage and commutation angle.

本文从带有高感性直流负载的三相全控整流电路稳态工作的物理情况出发，首先考虑了交流侧电感的影响，进而考虑交流侧电阻对直流电压、换相角的影响，将直流电压的平均值用麦克劳林级数表示，取前两项作近似，得出了实用的解析计算公式，并给出了计算步骤，实验证明该结果具有较高的精度。

The RMS—to—DC transformation is used for collecting virtual value of Ac. The voltage election elects the range of voltage. The analog—to—digital transformation realize transformation of measured voltage to corresponding digital figure. Finally the Sample Digital Display Ac Millivoltmeter is obtained.

其中RMS/DC专用芯AD637用来采集交流有效值转换，电压范围选择模块选择电压量程，模数转换使测量电压转换，最终得到所要求的数字显示交流毫伏表。

The main production of Self-healing low voltage shunt capacitor, AC motor soft starter intelligent, reactive power compensation controller, TBB series of low-voltage shunt capacitor devices, CBB60, CBB61, CBB65, CD60 series AC motor capacitors, metal pulse capacitor, magnetizing plane capacitor, ultraviolet lamp capacitor, split-phase shunt capacitor compensation, and other various low-voltage electrical products.

主要生产自愈式低电压并联电容器、交流电机智能软起动器，无功功率补偿控制器，TBB系列低压并联电容器装置、CBB60，CBB61，CBB65，CD60系列交流电动机电容器、金属化脉冲电容器、充磁机电容器、紫外线灯电容器、分相补偿并联电容器以及其它各种低电压电器产品。

Voltage Source and Current Source, Thevenin Theory, Trouble Shooting, Characteristic Curve of Diode, Diode Models, Rectifier Circuits, Input Filtering Capacitor, Voltage Multiplier Circuits, Limiter and Clipper Circuits, DC Clampers and Peak-to-peak Detectors, Zener Diode, Zener Diode Rectifier, Photoelectric Devices, Collector-Emitter Junction, Transistor Characteristics of common-emitter, Base Bias, LED Dirver, Establishing a Stable Q-point, PNP Transistor Biasing, Transistor Biasing, Coupling and By-Pass Capacitors, AC Emitter Resistance, Common-Emitter Amplifier, Other Common-Emitter Amplifiers, Cascaded Common-Emitter Amplifiers, AC Load Line, Emitter Follower, Class B Push-pull Amplifiers, JFET Characteristic Curve, JFET Biasing, JFET Amplifier, VMOS Circuit, Differential Amplifier, Operational Amplifier, Non-inverting Feedback, Negative Feedback.

电子学实验( S0704)(1，1)/应用电子学实验( S0472)(1，1)电压源和电流源、戴维宁定理、故障排除、二极体特性曲线、二极体近似模型、整流电路、电容-输入型滤波器、倍压电路、限制器电路和峰值检测电路、直流定位器与峰对峰检测器、齐纳二极体、齐纳二极体整流器、光电元件、集射极接面、集极特性曲线、基极偏压、LED驱动器、建立一个稳定的工作点 Q 、 PNP 电晶体偏压、电晶体偏压、耦合及旁路电容、交流射极电阻、共射极放大器、其他 CE 放大器、串接共射极放大器、交流负载线、射极随耦器、 B 类推挽式放大器、 JFET 特性曲线、 JFET 偏压、 JFET 放大器、 VMOS 电路、差动放大器、运算放大器、非反向电压回授、负回授。

Through the analysis of the work principle of three phases voltage resource PWM converter, set up the low and high mathematic models, deduce the restriction equations about grid voltage, grid current, modulation voltage and the DC output voltage and the calculation equations of the AC-side inductance and the DC-side capacitance. There are two control strategies are adopted: Predicted current control strategy and voltage-current two closed-loop control strategy, and give a comparison by theory and practice.

通过分析三相电压源型PWM变换器的工作原理，分别分析了低频和高频数学模型，并推导出了交流侧电压电流、调制电压、直流侧电压之间的数学约束关系以及交流侧电感和直流支撑电容参数的选取依据公式；分析对比了两种控制策略：预测电流控制和电压电流双闭环控制并加以实验验证；同时采用了负载电流前馈补偿和本文提出的一种基于专家系统的神经元新型智能PI控制器两种方法大大提高了整个系统的动态响应性能，并在仿真和实验中加以验证，这也是本文研究的重点内容之一。

The output is measured by a voltmeter or detector, such as precision voltmeters, ac measurement standards, ac/dc transfer standards, or thermal voltage converters, fitting them to a wide variety of metrology applications.

输出电压的测量或检测器，如精密电压表，交流计量标准，交流/直流转换标准，或热电压转换器，适合他们的各种计量应用。

CJX2－d Series AC contactor is mainly used in the ciruit AC 50HZ (or-60HZ),rated insulating voltage is 380V unde AC-3 usage it can be combined with suitable thermal overload equipment into a electromagnetic starter to protect the circuit that may appear overload The comactor can be equipped with builbing block style auxiliary con tact group、air delaying contact、Interlonking mechanism and so on ac cessories to combined into time relay、reversible comtactor and star-delta starter.

CJX2-d系列交流接触器主要用于交流50HZ（或60Hz，额定绝缘电压为660V，在AC-3使用类别下额定工作电压为380V时额定工作电流至95A的电器中，供远距离接通和分断电器，并可与适当的热过载电器组成电磁起动器以保护可能发生过载负荷的电路。接触器可组装积木式辅助触头组、空气延时头、联锁机构等附件；组成延时继电器、可逆接触器、星三角起动器。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。