查询词典 current amplifier

S1 is then changed to position 1. The voltage stored on C1 is inserted between the output and inverting input of the amplifier and the output of the amplifier changes by VIN to maintain the amplifier input at the input offset voltage. The output then changes from (VOS + IbiasR2) to (VIN + IbiasR2) as S1 is changed from position 2 to position 1. Amplifier bias current is supplied through R2 from the output of the amplifier or from C2 when S1 is in position 2 and position 1 respectively. R3 serves to reduce the offset at the amplifier output if the amplifier must have maximum linear range or if it is desired to DC couple the amplifier.

接着 S1 拨到位置 1，使 C1 的电压加在放大器的输出端和反相输入端之间，(由于电容端电压不能突变，所以)输出端的电压将产生大小等于 VIN 的变化，使放大器输入端维持输入失调电压，即当开关 S1 从位置 2 拨到位置 1 时，输出端电压将从(VOS + IbiasR2)变为(VIN + IbiasR2)。S1 处于位置 2 时，放大器的偏置电流是由输出端经电阻 R2 提供的，当 S1 转向位置 1 时则由 C2 提供。R3 的作用是降低输出失调电压，如果要求放大器具有最大的线性范围，或者采用直流耦合，就应该使用该电容。

The invention discloses a DC/DC circuit, comprising a PWM controller, a current amplifier, a peak current comparator, an error amplifier, a main switch, a synchronous switch and also an operational amplifier. The non inverting input end of the operational amplifier is used for coupling with input voltage or voltage reference, or used for coupling with the input voltage and the voltage reference; the inverting input end of the operational amplifier is used for coupling with the voltage reference or ground, and the output end thereof is connected with the non inverting input end of the error amplifier.

本发明公开了一种DC/DC电路，包括PWM控制器、电流放大器、峰值电流比较器、误差放大器、主开关和同步开关；还增设运算放大器，其同相输入端用于与输入电压或基准电压耦合，或用于同时与输入电压和基准电压耦合；其反相输入端用于与基准电压或地耦合，其输出端与所述误差放大器的同相输入端连接。

In this thesis the process of constructing the non-perturbative Hamiltonian theory is de-scribed and is applied to estimate the vacuum condensate. It contains the following contents:At the very beginning, by using the path integral method and eliminating the gluon freedom, aGCM action 〓 of current quarks including lower order current-current coupling was derivedfrom the QCD Lagrangian and the effective Hamiltonian operator that could hardly be doneby the normal methods was derived. After doing this, the broken vacuum is introduced whichincludes quark-antiquark condensate through the generalized Bogoliubov-Valatin transformation,the effective Hamiltonian of constituent quark was derived. The detailed formulas containingthe spatial current-current coupling term for the effective Hamiltonian and gap equations wasworked out by parameterizing the correlation kernel as a quadratic potential. And then, the gapequation was solved and the quark-antiquark condensate of vacuum was studied both in the casesof instantaneous interaction and retarded interaction. In the end, the effective Hamiltionian withtwo-body quark-quark interaction was derived with one-body approximation, and with the helpof the functional integral method the coupling non-linear dynamic equations for systems withnuclear matter was derived. Finally, these equations were solved by selfconsistent method andthe effect of nuclear matter on vacuum condensate was studied. The spatial current-current coupling term is too difficult to handle, hence the correlationkernel is assumed to be not important and usually omitted in the pure vacuum condensate, andthe instantaneous interaction generally is adopted. Retaining the spatial current-current termand partial retardation effect, the quark pairs condensate in pure vacuum was studied, and theeffect of quark mass was also studied. At present, little study is focused in the case with nuclearmatter and spatial current-current term also omitted. Under the approximation with partialspatial current-current term, the effect of nuclear matter on vacuum condensate was studied.

本论文描述了量子色动力学整体色对称模型哈密顿量方法的构建过程，得到了反映正反夸克对凝聚真空结构的关于组分夸克的有效哈密顿量算符，它隐含了胶子作用，并且准确至流-流耦合项；接着，通过参数化哈密顿量中的夸克作用关联核，导出平方禁闭势参数化选择的哈密顿量的具体公式和能隙方程；随后，应用公式，编程求解，考察了瞬时作用下和部分延迟作用下真空的正反夸克对凝聚，在计算中保留了空间流-流耦合作用；之后，导出瞬时势和延迟势下包含二体作用项的哈密顿量公式，并采用单体化近似，通过泛函变分方法得到核物质存在时耦合的非线性动力学方程；在保留部分空间双流耦合作用的近似下，求解核物质的动力学方程，考察核物质密度对真空凝聚的影响，以往考察真空凝聚，对关联核的选用，由于空间流-流耦合项不易处理，也认为作用不大，常忽略该项，并且常采用瞬时作用；本文保留空间双流项和部分延迟作用，考察了真空情形的夸克对凝聚，还考察了夸克质量对纯真空凝聚的影响，以往对核物质存在情形的真空凝聚考察很少，也都忽略空间流-流项，本文在考虑部分空间流-流项近似下，考察了核物质存在对真空凝聚的影响。

This kind of technology can flex the application of optical amplifier so that a same adaptive amplifier can be used as a pre-amplifier, a boost amplifier as well as a line amplifier.

在光标记交换系统中，可满足由于路由切换导致的光功率损耗大范围动态变化的应用需求。

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。

The ways of parallel resonant DC link and three-level control strategy were used in this power amplifier circuit. Output current ripple of power amplifier can be reduced as three-level power amplifier, all of power switches work on and off under the zero voltage switching or zero current switching, loss of switching and current ripple interference effectively reduced.

该电路在功率放大器三电平控制策略的基础上应用了并联谐振直流环节，保持了三电平功率放大器输出电流纹波小的优点，同时功率器件均工作在零电压或零电流条件下，开关损耗、电流纹波干扰有效地减小。

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。

For weak nonlinear distortion, the expressions of total harmonic distortion, the second order intermodulation distortion(IM2 ), the third order intermodulation distortion(IM 3) and intercept point(IP 3) are deduced. With the aid of software Multisim, we simulate transistor common emitter amplifier, transistor common emitter amplifier with resistor in emitter, differential amplifier and differential amplifier with resistor between emitters. The simulational results and theoretical analyses are almost the same.

针对弱非线性失真，推导了总谐波人、二阶互调失真( IM2 )、三阶互调失真( IM3)和截点( IP3)的表达式，借助于 Multisim软件，对晶体管共发放大器、发射极带反馈电阻的失发放大器、差分放大器和发射极间带反馈电阻的差分放大器进行了仿真，并与理论结果作了比较，结果令人满意。

Given that V2 is applied to the amplifier input lead, the high input resistance of the operational amplifier is the only load on V2, and the only current drawn from the source is the very low input offset current of the operational amplifier.

若V2加到放大器的输入端，运算放大器的高输入电阻成为V2的唯一负载，而且唯一从源吸取的电流是运算放大器非常低的输入偏置电流。

Whole-cellpatch-clamp technology demonstrated that VDPG (1g/L) had notsignificant effects on the delayed-rectified K~+ current, TTX-sensitive Na~+ current and high-voltage-activated Ca~(2+) current of rat dorsalroot ganglion cells. The fast transiet K~+ current of cottonbollworm dorsal DUM cells, the fast transiet K~+ current, Na~+ current andhigh-voltage-activated Ca~(2+) current of Periplaneta Americana dorsalunpaired median cells were also not significantly affected byVDPG at the same concentration. However, VDPG had significant effecton the fast transiet K~+ current of Pieris rapae. The VES had not significanteffects on the high-voltage-activated and low-voltage-activated Ca~(2+)current of rat DRG cells.

膜片钳电生理实验显示1g／L毒囊粗毒对蜚蠊DUM神经元的快瞬时钾电流、钠电流、高电压激活的钙电流，对棉铃虫快瞬时钾电流和大鼠DRG细胞延迟整流钾电流、TTX-S型钠电流、高电压激活的钙电流均无明显作用，却对菜青虫快瞬时钾电流有明显作用；电刺激粗毒对大鼠DRG细胞低电压和高电压激活的钙通道无明显作用。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。