A light-emitting diode (LED) is a semiconductor device that emits narrow-spectrum incoherent light when forward-biased.The color of the emitted light depends on the chemical composition of the semiconductor material used, and can benear-ultraviolet, visible or infrared. LEDs are more prevalent today than ever before, replacing traditional incandescent andfluorescent bulbs in many lighting applications. Incandescents use a heated filament, are subject to breakage and burnoutand operate at a luminous efficiency of 2% to 4%. Fluorescents are more efficient, at 7% to 12%, but require highdrive voltage and contain mercury, a toxic substance that may be eventually banned in certain countries. LEDs, however,produce light directly through electroluminescence, operate at low voltage and can deliver over 20% luminous efficiency.
上傳時(shí)間： 2013-11-07
上傳用戶：xiaoyuer
Abstract: Investment in smart meters and smart grid end equipment continues to grow worldwide as countriestry to make their electric delivery systems more efficient. However, as critical as the electric deliveryinfrastructure is, it is normally not secured and thus subject to attack. This article describes the concept oflife-cycle security—the idea that embedded equipment in the smart grid must have security designed into theentire life of the product, even back to the contract manufacturer. We also talk about how life-cycle securityapplies to embedded equipment in the smart grid. Potential threats are discussed, as are potential solutionsto mitigate the risks posed by those threats.
標(biāo)簽： 智能電表 智能電網(wǎng)
上傳時(shí)間： 2014-12-24
上傳用戶：熊少鋒
Advancements in board assembly, PCB layout anddigital IC integration have produced a new generationof densely populated, high performance systems. Theboard-mounted point-of-load (POL) DC/DC power suppliesin these systems are subject to the same demandingsize, high power and performance requirements asother subsystems. The rigorous new POL demands aredifficult to meet with traditional controller or regulatorICs, or power modules.
上傳時(shí)間： 2014-12-24
上傳用戶：lbbyxmraon
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(shí)間： 2014-12-27
上傳用戶：Tracey
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their productsor to discontinue any product or service without notice, and advise customers to obtain the latestversion of relevant information to verify, before placing orders, that information being relied onis current and complete. All products are sold subject to the terms and conditions of sale suppliedat the time of order acknowledgement, including those pertaining to warranty, patentinfringement, and limitation of liability.
標(biāo)簽： Assembly Language C6000 320C
上傳時(shí)間： 2013-11-12
上傳用戶：chens000
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their productsor to discontinue any product or service without notice, and advise customers to obtain the latestversion of relevant information to verify, before placing orders, that information being relied onis current and complete. All products are sold subject to the terms and conditions of sale suppliedat the time of order acknowledgement, including those pertaining to warranty, patentinfringement, and limitation of liability
上傳時(shí)間： 2013-12-26
上傳用戶：凌云御清風(fēng)
When I started writing the first edition of RF Power Amplifiers for Wireless Communications,some time back in 1997, it seemed that I was roaming a largely uninhabitedlandscape. For reasons still not clear to me there were few, if any, otherbooks dedicated to the subject of RF power amplifiers. Right at the same time, however,hundreds of engineers were being assigned projects to design PAs for wirelesscommunications products. It was not, therefore, especially difficult to be successfulwith a book that was fortuitously at the right place and the right time.
標(biāo)簽： Communications Amplifiers Wireless Edition
上傳時(shí)間： 2013-11-12
上傳用戶：YYRR
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
標(biāo)簽： 射頻 基礎(chǔ)知識(shí)
上傳時(shí)間： 2013-10-23
上傳用戶：685
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
標(biāo)簽： 無(wú)線技術(shù)
上傳時(shí)間： 2013-10-08
上傳用戶：kinochen
The information in this specification is subject to change without notice.Use of this specification for product design requires an executed license agreement from the CompactFlashAssociation.The CompactFlash Association shall not be liable for technical or editorial errors or omissions contained herein; norfor incidental or consequential damages resulting from the furnishing, performance, or use of this material.All parts of the CompactFlash Specification are protected by copyright law and all rights are reserved. Thisdocumentation may not, in whole or in part, be copied, photocopied, reproduced, translated, or reduced to anyelectronic medium or machine readable form without prior consent, in writing, from the CompactFlash Association.The CFA logo is a trademark of the CompactFlash Association.Product names mentioned herein are for identification purposes only and may be trademarks and/or registeredtrademarks of their respective companies.© 1998-99, CompactFlash Association. All rights reserved.
標(biāo)簽： 技術(shù)資料
上傳時(shí)間： 2013-10-08
上傳用戶：stewart·
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