电路

With the calculating the damping circuit parameter of traction coil on SS4G type electric locomotive ,the reasons of the frequently burning down is analyzed,and the method of calculating damping circuit parameter is concluded.

通过对 SS4G型电力机车牵引绕组阻尼电路参数的计算，分析了阻尼电路频繁损坏的可能原因，并归纳了阻尼电路参数的计算方法，最后提出了阻尼电路参数的改进建议。

On the basis of the above results of detecting methods, the instruction signal calculating circuit is designed according to i〓, i〓 calculating mode. Compensation current generating circuit is also designed and implemented. Its current following circuit is designed according to the instantaneous value comparing mode that used constant time control. The source current detection based control mode and composite control mode and their implementation are firstly introduced in our country. The method and the principle of dc side capacitor voltage control are explained clearly.

根据检测方法的研究成果，采用i〓、i〓运算方式构成并联型电力有源滤波器的指令电流运算电路；对补偿电流发生电路进行了电路设计和实施，其中电流跟踪控制电路采用电流跟随性能好、可靠性高的定时控制瞬时值比较方式；在国内首次研究并实施检测电源电流控制方式和复合控制方式；清楚地阐明了并联型电力有源滤波器直流侧电压控制的原理和方法，并在装置中实施。

Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

Most people consider the return current when considering a fully differential circuit, but when considering the more usual circuit where a signal is referred to 'ground' it is common to assume that all the points on the circuit diagram where the ground symbol is to be found are at the same potential.

分析差分电路时，绝大多数工程师都会注意到返回电流，但对于常见的所谓单端电路，即所有信号采用相同参考点的电路，往往会认为电路中所有标有参考点符号的地方电平都相等。

The invention relates to an amplifier circuit containing a high-frequency transistor (1) and having a circuit (2) for adjusting the operating point, which provides a base current for the high-frequency transistor (1) according to the voltage released at a resistor (3) which is connected in the collector ring of the high-frequency transistor (1). The circuit (2) has a differentiating unit (20), fed by the supply voltage, which compares the voltage released at the resistor (3) with a reference voltage.

带有高频晶体管(1)的放大器电路具有一个用于工作点调整的电路(2)，其依赖于在连接在高频晶体管(1)的集电极电路中的电阻(3)上下降的电压为高频晶体管(1)提供基极电流，电路(2)具有一个由供电电压馈电的差分节(20)，其把在电阻(3)上下降的电压与基准电压比较。

Analyze the example we proof: we can get the most simple Combinational Logic Circuits by the Communal technique to design Combinational Logic Circuits., and the combinational logic circuits's rate of function and price was improved.

通过实例的分析证明了使用公用技术组合逻辑电路设计方法实现的逻辑电路比使用最简逻辑函数实现的逻辑电路更简单，从而提高了逻辑电路的性价比。

For the circuit to work,of course,polarities of both the base and collector circuits have to be correctforward bias applied to the base circuit,and the collector supply connected so that the polarity of the common element(the emitter is the same from both voltage sources.

对于电路的工作来说，当然，基极和集电极电路是需要更正的（正向偏置电压加在基极电路和集电极电路以便于发射极的电压极性和电压源的电压极性是相同的。

With this mode of working the base-emitter circuit is the input side;and the emitter through base to collector circuit the output side.although these have a common path through base and emitter, the two circuit are effectively separated by the fast that as far as polarity of the base circuit is concerned,the base and upper half of the transistor are connected as a reverse biased diode.hence there is no current flow from the base circuit into the collector circuit.

这一工作模式下，基极-发射极电路是输入端，发射极通过基极，再到集电极电路的输出端。虽然它们都有一个共同的路径通过基极和发射极，这两个电路是通过和基极电路相关的尽可能的有效快速分离开的，基极和基极以上的一半以上的晶体管作为一个反偏二极管与之相连接。

In this paper the commutate circuit principle and work process of the commutate circuit, the composing and work principle of frequency conversion circuit, main switch element IGBT structure feature turn on and turn-off process dynamic and static switch feature and the work principle of invert were analyzed .

本论文分析了整流电路及相控电路的原理和工作过程；变频电路的组成和工作原理；主开关器件IGBT的结构特点、导通及关断过程、动态静态开关特性；逆变电路的工作原理。

The contravariant welding machine main circuit system by the input filter leveling circuit, the contravariant electric circuit, the high-frequency transformer, the output rectification filter circuit is composed.

主电路系统由输入滤波整流电路、逆变电路、高频变压器、输出整流滤波电路组成。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。