As the performance of many handheld devices approachesthat of laptop computers, design complexity also increases.Chief among them is thermal management—how doyou meet increasing performance demands while keepinga compact and small product cool in the user’s hand?For instance, as battery capacities inevitably increase,charge currents will also increase to maintain or improvetheir charge times. Traditional linear regulator-based batterychargers will not be able to meet the charge currentand effi ciency demands necessary to allow a product torun cool. What is needed is a switching-based chargerthat takes just about the same amount of space as a linearsolution—but without the heat.
上传时间： 2013-11-23
上传用户：lu2767
Specifying the right reference and applying it correctly isa more difficult task than one might first surmise, consideringthat references are only 2- or 3-terminal devices.Although the word “accuracy” is most often spoken inreference to references, it is dangerous to use this wordtoo freely because it can mean different things to differentpeople. Even more perplexing is the fact that a referenceclassified as a dog in one application is a panacea inanother. This application note will familiarize the readerwith the various aspects of reference “accuracy” andpresent some tips on extracting maximum performancefrom any reference.
标签： 电压基准
上传时间： 2013-10-15
上传用户：liuwei6419
Occasionally, we are tasked with designing circuitry for aspecific purpose. The request may have customer originsor it may be an in-house requirement. Alternately, a circuitmay be developed because its possibility is simply tooattractive to ignore1. Over time, these circuits accumulate,encompassing a wide and useful body of proven capabilities.They also represent substantial effort. These considerationsmake publication an almost obligatory propositionand, as such, a group of circuits is presented here. This isnot the first time we have displayed such wares and, giventhe encouraging reader response, it will not be the last2.Eighteen circuits are included in this latest effort, roughlyarranged in the categories given in this publication’s title.They appear at the next paragraph.
上传时间： 2013-11-12
上传用户：012345
Analog Inputs and Outputs in an S7 PLC are represented in the PLC as a 16-bit integer. Over the nominal span of the analog input or output, the value of this integer will range between - 27648 and +27648. However, it is easier to use the analog values if they are scaled to the same units and ranges as the process being controlled. This applications tip describes methods for scaling analog values to and from engineering units.
上传时间： 2013-11-17
上传用户：3294322651
Digitemp Junior – An RS-232 Port-Powered Digital Thermometer Digitemp Jr. is a device that is designed to measure and report ambient temperature. When connected to an RS-232 port on any PC, it will periodically measure and report in ASCII form the ambient temperature in degrees Celsius. These temperature readings can be monitored with any terminal program. If the terminal program supports capture to disk, the temperature readings can be saved to disk for further analysis with a spreadsheet program or other data analysis tool. The simple ASCII output format of Digitemp Jr. makes it rel- atively easy to write custom software for receiving, recording, and analyzing ambient temperature data. Best of all, Digitemp Jr. requires no external power sup- plies or batteries. It is powered directly by the RS-232 port.
上传时间： 2013-10-21
上传用户：baitouyu
Digitemp Jr. is a device that is designed to measure and report ambient temperature. When connected to an RS-232 port on any PC, it will periodically measure and report in ASCII form the ambient temperature in degrees Celsius. These temperature readings can be monitored with any terminal program. If the terminal program supports capture to disk, the temperature readings can be saved to disk for further analysis with a spreadsheet program or other data analysis tool. The simple ASCII output format of Digitemp Jr. makes it relatively easy to write custom software for receiving, recording, and analyzing ambient temperature data. Best of all, Digitemp Jr. requires no external power supplies or batteries. It is powered directly by the RS-232 port.
上传时间： 2013-10-20
上传用户：Maple
基于CC1110单片机公交报站系统主要由CC1110单片机最小系统和WT588D语音模块组成，提出了如何实现语音报站，通过无线通信SimpliciTI网络协议实现公交站台的自动播报和OLCD液晶显示公交运行的各类信息。结果表明，该公交报站系统报站准确率99%，价格比同类产品下降了300%以上，系统组成结构简单，提高了系统的抗干扰性和稳定性，也便于携带。 Abstract: The bus stop announcement system based on CC1110 MCU is composed of CC1110 MCU minimum system and WT588D voice module. How to achieve the voice announcing is put forward.The bus-stop will announce automatically and display on the OLCD by means of wireless communication SimpliciTI network protocol. As a result， the bus station stop announcement systems reported 99% accuracy rate， price of similar products declined by 300% or more， system of simple structure， improve the anti-jamming and stability of the power system， it is also portable.
上传时间： 2013-10-21
上传用户：baby25825
针对材料试验机等设备中要求测量或控制材料拉伸或压缩的位移，一般采用光电轴角编码器检测位置信号，输出正交编码脉冲信号。若采用其他方法检测位置信号，必然导致电路设计复杂，可靠性降低。因此，提出一种基于LS7266R1的电子式万能材料试验机设计方案。给出了试验机中的控制器工作原理，LS7266R1与单片机的接口硬件设计，以及主程序软件流程图。巧妙地把力量传感器，位移传感器等机械运动状态的压力或拉力以及位置坐标，变成了电压信号和电脉冲数字信号，供A/D测量和LS7266R1计数，从而实现了独立完成材料试验控制或通过PC机串口命令完成材料试验控制。 Abstract: Aiming at the requirement that the displacement of the tension and compression always be tested and controlled in the equipement such as material testing machine. The position signal was tested by photoelectric axial angle coder. Therefore， the paper proposes the design of electronic universal testing machine design based on LS7266R1. If the position signal detected by other methods， will inevitably lead to the circuit design complexity， reliability decreased. The work theory of the controller， the hardware interface design between LS7266R1 and single chip， and the flow chart of main program， are presented in this paper. The signal of the compression or tension power and displacement at working， which tested by power sensor and displacement sensor especially， is changed into electric voltage and electric pulse numerical signals. And these signals can be tested by A/D and counted by LS7266R1. Finally the test of the material properties can be controlled by itself， or controlled by the COM command of PC.
上传时间： 2013-11-02
上传用户：yl1140vista
介绍了一种基于MSP430系列单片机和ADXL203加速度传感器的数字式倾角仪，它不仅可以实现水平度检测，而且可以测量00～3600范围内的任意倾角，分辨率可达O．1。。此外，由于该倾角仪输出为数字结果，因此它也可以与其他的数字设备结合起来，组合成一个功能更加强大的仪器。该数字倾角仪可广泛应用于建筑、机械、道路、桥梁、石油、煤矿和地质勘探等各种需要测量重力参考系下倾角的场合。关键词：MSP430F133单片机；力敏传感器；ADXL203加速度计；角度测量 Abstract：This paper presents a new style digital inclinometer which is developed on the basis of the MSP430F133 MCU and the ADXL203 dual axis aeeelerometer．This inclinometer not only can test levelness，but also can measure any angle between 0。and 360。with an accuracy of 0．1 O．In addition，its output is a digital result，which makes it possible to integrate itself with other digital devices to form a more functional unit．This inclinometer can be widely used in any construction site，oil field，coal-mine or geologic survey and SO on where it will provide the working people with convenience to measure any angles．Key words：MSP430F133 MCU；force sensor；ADXL203 accelerometer；angle measurement
上传时间： 2013-11-14
上传用户：lizhizheng88
PICkit™ 2 Microcontroller Programmer USER’S GUIDE This chapter contains general information that will be useful to know before using thePICkit™ 2 Microcontroller Programmer. Items discussed in this chapter include:• Document Layout• Conventions Used in this Guide• Warranty Registration• Recommended Reading• The Microchip Web Site• Development Systems Customer Change Notification Service• Customer Support• Document Revision History
标签： Microcontrolle PICkit 8482
上传时间： 2013-11-05
上传用户：妄想演绎师
