Abstract: The "vampire" drain on electricity by household gadgets is only one indicator of the lack of policies to conserve energy and protect people and businesses from a major energy disaster. Most
上傳時間： 2013-11-18
上傳用戶：wgh_kf
Although recent popular attention is focused on LithiumIon batteries, one must not forget that other batterychemistries, such as Nickel Cadmium (NiCd) and NickelMetal Hydride (NiMH) have advantages in rechargeablepower systems. Nickel-based batteries are robust, capableof high discharge rates, have good cycle life, do notrequire special protection circuitry and are less expensivethan Li-Ion. Among the two, NiMH batteries are rapidlyreplacing NiCd because of their higher capacity (40% to50% more) and the environmental concerns of the toxiccadmium contained in NiCd batteries.
上傳時間： 2013-11-04
上傳用戶：qq10538412
One of the fi rst lessons in a basic electronics coursecovers the symbols for resistors, capacitors, inductors,voltage sources and current sources. Althougheach symbol represents a functional component of areal-world circuit, only some of the symbols have directphysical counterparts. For instance, the three discretepassive devices—resistors, capacitors, inductors—canbe picked off a shelf and placed on a real board muchas their symbolic analogs appear in a basic schematic.Likewise, while voltage sources have no direct 2-terminalanalog, a voltage source can be easily built with an offthe-shelf linear regulator.
上傳時間： 2013-11-24
上傳用戶：simonpeng
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.
標簽： 電壓基準
上傳時間： 2013-10-15
上傳用戶：liuwei6419
For a variety of reasons, it is desirable to charge batteriesas rapidly as possible. At the same time, overchargingmust be limited to prolong battery life. Such limitation ofovercharging depends on factors such as the choice ofcharge termination technique and the use of multi-rate/multi-stage charging schemes. The majority of batterycharger ICs available today lock the user into one fixedcharging regimen, with at best a limited number ofcustomization options to suit a variety of application needsor battery types. The LTC®1325 addresses these shortcomingsby providing the user with all the functionalblocks needed to implement a simple but highly flexiblebattery charger (see Figure 1) which not only addressesthe issue of charging batteries but also those of batteryconditioning and capacity monitoring.
上傳時間： 2013-10-19
上傳用戶：royzhangsz
為了改變目前電網現場作業管理的變電巡檢、變電檢修試驗、輸電線路巡檢檢修等管理系統各自獨立運行，信息不能共享，功能、效率受限，建設和維護成本高的現狀，提出了采用B/S+C/S構架模式，將各現場作業管理模塊和生產MIS（管理系統）集成為一體的現場作業管理系統的設計方案，做到各子系統和生產MIS軟硬資源共享，做到同一數據唯一入口、一處錄入多處使用。各子系統設備人員等基礎信息來源于生產管理系統，各子系統又是生產管理系統的作業數據、缺陷信息的重要來源。經過研究試用成功和推廣應用，目前該系統已在江西電網220 kV及以上變電站全面應用。 Abstract: In order to improve the status that the substation field inspection system， substation equipments maintenance and testing system， power-line inspection and maintenance system are running independent with each other. They can?蒺t share the resource information which accordingly constrains their functions and efficiency， and their construction and maintenance costs are high. This paper introduces a field standardized work management system based on B/S+C/S mode， integrating all field work management systems based on MIS and share the equipments and employee?蒺s data of MIS，the field work data of the sub systems are the source information of MIS， by which the same single data resouce with one-time input can be utilized in multiple places. After the research and testing， this system is triumphantly using in all 220kV and above substations in Jiangxi grid.
上傳時間： 2013-11-15
上傳用戶：han_zh
鎖定放大是微弱信號檢測的重要手段。基于相關檢測理論，利用開關電容的開關實現鎖定放大器中乘法器的功能，提出開關電容和積分器相結合以實現相關檢測的方法，并設計出一種鎖定放大器。該鎖定放大器將微弱信號轉化為與之相關的方波，通過后續電路得到正比于被測信號的直流電平，為后續采集處理提供方便。測量數據表明鎖定放大器前級可將10-6 A的電流轉換為10-1 V的電壓，后級通過帶通濾波器級聯可將信號放大1×105倍。該方法在降低噪聲的同時，可對微弱信號進行放大，線性度較高、穩定性較好。 Abstract: Lock-in Amplifying（LIA）is one of important means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
上傳時間： 2013-11-29
上傳用戶：黑漆漆
介紹了基于單片機C8051F020的通用串口適配器的設計與實現方法，即由單片機控制的智能化一對多口收發信號轉換器。通過采用C51對單片機進行編程，控制與RS-232（標準RS-232電平）、RS232(TTL電平)、RS-422接口的數據通信；采用C++ Builder作為開發平臺，通過RS-232接口實現上位機對適配器各個通信端口的控制。 Abstract: Design and realization of a universal serial port adapter based on the MCU C8051F020 are introduced.The adapter is an intelligent one-to-more receiving and transmitting signal converter controlled by the MCU. By programming the MCU with the language C51,MCU control data communication between the MCU and RS-232(RS-232 level),RS-232(TTL level),RS-422 port; Using C++ Builder as the development plane, by one RS232 port, the upper PC can control each of the communication port of the adapter.
上傳時間： 2013-11-19
上傳用戶：hebanlian
為了在工業生產及過程控制中準確測量溫度，設計了一種基于低功耗MSP430單片機的數字溫度計。整個系統通過單片機MSP430F1121A控制DS18B20讀取溫度，采用數碼管顯示，溫度傳感器DS18B20與單片機之間通過串口進行數據傳輸。MSP430系列單片機具有超低功耗，且外圍的整合性高，DS18B20只需一個端口即可實現數據通信，連接方便。通過多次實驗證明，該系統的測試結果與實際環境溫度一致，除了具有接口電路簡單、測量精度高、誤差小、可靠性高等特點外，其低成本、低功耗的特點使其擁有更廣闊的應用前景。 Abstract: In order to obtain accurate measuring temperature in industrial production and process control， a digital thermometer based on MSP430 MCU is designed. The system uses MSP430F1121A MCU to control DS18B20， and gets the temperature data， which is displayed on the LED. The temperature sensor DS18B20 and MCU transmit data through serial communication. MSP430 series has ultra-low power and high integration， DS18B20 only needs one port to achieve data communication. Through many experimental results prove， this system is consistent with actual environment temperature. The system has characteristics of interface circuit simple， high measuring accuracy， minor error， high reliability， besides， the characteristics of low cost and low power make it having vaster application prospect.
上傳時間： 2013-10-16
上傳用戶：wettetw
Information in this document is subject to change without notice and does notrepresent a commitment on the part of the manufacturer. The software describedin this document is furnished under license agreement or nondisclosureagreement and may be used or copied only in accordance with the terms of theagreement. It is against the law to copy the software on any medium except asspecifically allowed in the license or nondisclosure agreement. The purchasermay make one copy of the software for backup purposes. No part of this manualmay be reproduced or transmitted in any form or by any means, electronic ormechanical, including photocopying, recording, or information storage andretrieval systems, for any purpose other than for the purchaser’s personal use,without written permission.
上傳時間： 2014-12-27
上傳用戶：Tracey
