转换开关

The steady-state operating characteristics of the proposed DC-DC converter topology are illustrated and discussed on the basis of the simulation and some experimental results of 2kW-4OHz breadboard set up.

不过，大部分的零电压开关PWM DC - DC变换器发达以前，包括一些弊端，如负荷依赖软开关运作，相对狭小的范围和零电压转换器效率降低，由于大循环电流流经。

This high voltage electrostatic precipitation controller has 7 channels of analog input,2 channels of analog output, 12 digital inputs and 16 digital outputs. The analog input includes primary current, secondary current, primary voltage, secondary voltage, etc. Controller uses MAX 187 as the A/D converter, which ensure the sampling speed and the conversion precision in the same time. The processor unit is RCM2250 module. Rabit 2000 processor, a 128K SRAM and a 256K Flash Rom are integrated in RCM2250, which improves the performance of pricipitation controller. MAX504 is used to produce the 4~20mA current output.

模拟量输入采集的信号有升压变压器一次电流、一次电压、二次电流、二次电压等，采用12位逐次比较式A/D转换器MAX187，兼顾采样速率和转换精度；中央处理单元采用以8位嵌入式处理器Rabbit2000为基础的RCM2250模块，外扩128KSRAM和256K Flash ROM，内部资源丰富，提高了控制器的整体性能；模拟量输出采用内带基准源的10位电压输出数模转换器MAX504，实现了标准4～20mA电流信号输出；控制器通过控制算法在相应开关量点上输出可控硅的触发脉冲。

In the data acquisition system, CD4051 and AD574- the A/D transform, are used as hard core to receive the signal from the infra-red ray temperature sensor; the data acquisition depend on CPU; in the keyboard/ display system, a 74LS48 as the driver to drive LED works; in the warning circuit, I used two color LED and a buzzer as one unit to work; DAC0832 converter is the center of the D/A transform; execution unit, I used DDZIII type electromotive unit; the auto-man, it is a disabling of the other control circuit, this can secure production all the time.

在数据采集部分，以多路开关CD4051和AD574模/数转换器为核心接收来自红外线传感器的信号；数据处理依赖CPU；键盘/显示部分，以74LS48驱动LED数码管工作；报警单元，采用了双色LED加蜂鸣器的组合；D/A转换采用了DAC0832转换器；执行器采用DDZIII型电动执行器；手/自动切换装置则屏蔽了之前的电器部分，安全可靠。

In this topology, the main switches are operated under ZVS due to commutation of the transformer magnetizing current and the parasitic drain-source capacitance.

在此转换器，其主要开关主要是利用变压器的激磁电流和开关本身内部的寄生电容的换向，使得主开关操作於零电压的模式底下。

It is characterized by : the mechanical mouse moves and rolling around key operations into switching signals Circuit square with the square wave signal to substitute for the original mouse photosensitive sensors within the pulse signal, using the switch can be achieved mouse cursor movement and the mouse double-click a single operation, and the use of transmitting and receiving circuits instead of the mouse line, a remote-control mouse.

其特征是：将机械鼠标的滚动动作和左右键的作转换成开关信号，用方波电路产生的方波信号代替原鼠标内光敏传感器的脉冲信号，用相应的开关动作可以实现鼠标光标移动和鼠标的单双击作，而用发射和接收电路代替原来的鼠标线，可以实现鼠标的遥控。

ICL(7106)3_(1/2) bit A/D convertor through the encoder convert the sectional code into BCD code. The BCD output is interfaced with the microcomputer system,when through se- veral aualog channel qnantity is collected we can use the multiplexor. Our experiment has proved that the system has simple circuit with reliabe operation and it is cheap.

本文介绍了 ICL(7107)3_(1/2)位 A/D 转换器段码输出与微机系统的接口电路，ICL(7106)3_(1/2)位 A/D 转换器经编码器，将段码转换为 BCD 码输出与微机系统收接，当对多个模拟量进行检测时可应用多路开关，实验证明联接线路简单，运行可靠，装置便宜。

The results show that the propagation delay is less than 1ns, the ratio of input and output impedance is up to 10〓, realizing a little insert dissipation at high-speed operation, laying a solid foundation for the materialization of high-resolution one-way analog switch A/D converter. 2. A new structure of the high-speed CMOS voltage comparator circuit for the improved nonoffset cancel circuit, which can satisfy the needs of the 8-bit linearity.

模拟结果表明，基于CMOS工艺实现的BiCMOS单向模拟开关的传播延迟小于1ns，开关的输入输出阻抗比高达10〓以上，实现了高速工作下的极小插入损耗，为实现高精度单向隔离模拟开关分步法A/D转换器奠定了基础； 2、基于满足八位线性要求的前提，本文提出了一种改进的无失调取消电路的高速CMOS电压比较器新结构。

All of these power MOSFETs are designed for applications such as switching regulators, switching convertors, motor drivers, relay drivers, and drivers for high power bipolar switching transistors requiring high speed and low gate drive power.

所有这些功率MOSFET的设计，例如开关稳压器的应用，开关转换器，电机驱动器，继电器驱动器，驱动器和高功率双极晶体管的开关速度和低要求高栅极驱动力。

Problems to be overcome, according to the researchers, include volatility—the voltage has to be kept on to retain the switch state; slow switching speeds—about 10 kilohertz in the prototype; and a tendency of the switch to freeze permanently closed after a large number of cycles.

依照研究人员的说法，这项技术还需克服的问题包括：挥发性（须继续施加电压以保持开关状态，减缓转换速度）原型开关中的速度约为10千赫，以及开关在经过许多次循环后有发生永久性冻结的倾向。

However, when the switches are working as linear mode, the relations between the wide output electromagnetic pulse and biased dc voltage, trigging condition, and a function between the transforming efficiency and biased dc voltage, trigging condition need father research.

然而，当开关工作于线性模式时，开关的输出电脉冲的宽度与偏置电压和触发条件的关系、开关的转换效率与触发条件及偏置电压确切关系还需进一步研究。

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。