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.
上传时间： 2013-11-07
上传用户：xiaoyuer
As environmental concerns over traditional lighting increaseand the price of LEDs decreases, high power LEDsare fast becoming a popular lighting solution for offl ineapplications. In order to meet the requirements of offl inelighting—such as high power factor, high effi ciency, isolationand TRIAC dimmer compatibility—prior LED driversused many external discrete components, resulting incumbersome solutions. The LT®3799 solves complexity,space and performance problems by integrating all therequired functions for offl ine LED lighting.
上传时间： 2013-10-13
上传用户：dongqiangqiang
Once relegated to the hinterlands of low cost indicatorlights, the LED is again in the spotlight of the lightingworld. LED lighting is now ubiquitous, from car headlightsto USB-powered lava lamps. Car headlights exemplifyapplications that capitalize on the LED’s clear advantages—unwavering high quality light output, tough-assteelrobustness, inherent high effi ciency—while a USBlava lamp exemplifi es applications where only LEDs work.Despite these clear advantages, their requirement forregulated voltage and current make LED driver circuitsmore complex than the venerable light bulb, but some newdevices are closing the gap. For instance, the LTM®8040μModule™ LED driver integrates all the driver circuitryinto a single package, allowing designers to refocus theirtime and effort on the details of lighting design criticalto a product’s success.
上传时间： 2013-10-16
上传用户：togetsomething
提出了一种基于C8051F320的列车安全巡检仪的设计方案，详细阐述了巡检仪的各个模块的硬、软件设计。巡检仪集信息采集、轴温检测、照明和记录存储等功能于一体，实现了对列车安全巡检工作有效的监督和科学管理。系统软件采用C51编写，对单片机进行有效的电源管理，保证了巡检仪的稳定性、可靠性和低功耗性。 Abstract: This paper puts forward a design of train safety inspection based on C8051F320,describes all modules hardware and software design of inspection instrument.The inspection instrument has the function of information collection, axle’s temperature detection, lighting and records storage.It can supervise and administer train safety inspection work effectively.The system software using C51 can manage the power of single chip microcomputer, and guarantee the stability, reliability and low power consumption of the inspection instrument.
上传时间： 2013-12-22
上传用户：落花无痕
Abstract: This application note explains how to design an intelligent lighting controller that senses and measures the ambient lightlevel with an ambient light sensor (ALS). Equipped with a real-time clock (RTC), the controller also knows when to turn lighting on oroff at specified times. The system presented in this document can be used to control all luminaires that are mains-supply operated.Controller software is also provided in hex format.
上传时间： 2013-11-18
上传用户：AbuGe
he LPC932 can be used to create a Pulse Width Modulated PWM signal. That s an analog signal, with only 2 discrete levels, for example 0V and 5V and a constant period. The current value of this signal at a certain poiTnt of time is proportional to its Duty Cycle. That s the High Time during one period divided by the period. It can also be calculated as the average value during a particular period. That means after low pass filtering, (e.g. RC circuit) the signal becomes analog, with an actual value controlled by the microcontroller. The PWM functionality enables the LPC932 to control for example the speed of DC motors or the brightness of electric lighting.
标签： signal Modulated analog create
上传时间： 2015-05-14
上传用户：CHINA526
The goal of this project is to explore the idea of point-based radiosity, which is a shooting radiosity technique suggested by Mark Harris at UNC. The primary idea is that features available in graphics hardware can be utilized to perform radiosity calculations. Facilities such as flat shading, diffuse lighting, projective textures, and mipmapping can be used to replace traditional numerical solutions for radiosity.
标签： point-based radiosity shooting explore
上传时间： 2015-08-24
上传用户：change0329
We propose a novel approach for head tracking, which combines particle filters with Isomap. The particle filter works on the low-dimensional embedding of training images. It indexes into the Isomap with its state variables to find the closest template for each particle. The most weighted particle approximates the location of head. We develop a synthetic video sequence to test our technique. The results we get show that the tracker tracks the head which changes position, poses and lighting conditions.
标签： approach combines particle tracking
上传时间： 2016-01-02
上传用户：yy541071797
This demonstration shows how a ZigBee coordinator can be set up. This demo allows the Demonstration Board (PICDEM Z or Explorer 16) to act as either a "Switching Load Controller" (e.g. a light) or a "Switching Remote Control" (e.g. a switch) as defined by the Home Controls, lighting profile. It is designed to interact with a second Demonstration board programmed with the Demo RFD project
标签： This demonstration Demonstratio coordinator
上传时间： 2014-01-18
上传用户：dianxin61
Programming the USB2DMX by Jan Menzel 3rd January 2002 Abstract This document describes how the USB2DMX DMX512 interface for the USB-port by lighting- Solutions1 has to be programmed. It includes all information the software engineer has to supply to the operating systems USB-stack to talk to the USB2DMX
标签： Programming the describes Abstract
上传时间： 2016-10-31
上传用户：SimonQQ
