Microfluidics — a lab in your palm

A few decades ago electronics evolved from huge circuits based on vacuum tubes into small scale semiconducting integrated circuits. In simple words, a calculator that was as huge as a room, now fits into a wrist watch. Nowadays, a similar trend is observed in bio and chemical engineering. Analysis and synthesis involving fluids, which originally could be done only on large scales, are more and more integrated into small devices called microfluidic chips. Such microsacle or even nanoscale devices, in general called lab-on-a-chip devices, offer a higher accuracy and better efficiency compared to bulk devices. In this article we describe some important aspects about microfluidics.     

The Moore＇s Law for photonic integrated circuits

We formulate a ＂Moore＇s law＂ for photonic integrated circuits （PICs） and their spatial integration density using two methods. One is decomposing the integrated photonics devices of diverse types into equivalent basic elements, which makes a comparison with the generic elements of electronic integrated circuits more meaningful. The other is making a complex component equivalent to a series of basic elements of the same functionality, which is used to calculate the integration density for functional components realized with different structures. The results serve as a benchmark of the evolution of PICs and we can conclude that the density of integration measured in this way roughly increases by a factor of 2 per year. The prospects for a continued increase of spatial integration density are discussed.     

How Young Children Understand Electric Circuits: Prediction,explanation and exploration

This paper reports findings from a study of young children’s views about electric circuits. Twenty‐eight children aged 5 and 6 years were interviewed. They were shown examples of circuits and asked to predict whether they would work and explain why. They were then invited to try out some of the circuit examples or make circuits of their own choosing. Children expressed a variety of views about the connections needed in a circuit, offered different kinds of explanation and showed differing levels of competence in circuit making. The range of responses showed similarities to those of older students found in previous research. The relationship between practical competence, prediction, and explanation was not straightforward. For example, children with similar levels of practical competence made different predictions or offered different kinds of explanation. Analysis of the circuits children chose to construct suggested influences of existing competence and knowledge. In particular, some children tested out circuit examples about which they had been unsure during the interview, while others explored circuit connections more generally. Findings underline the importance of drawing on a variety of evidence in assessing young children’s understandings of electric circuits. They indicate that young children may offer views about electric circuits not unlike those of older children and adults with similar experience. Finally, there was some suggestion that the interview procedure may have acted as an instructive stimulus in helping children to become more conscious of their own views and reflect on their thinking in the light of further evidence.     

常用数字集成电路的使用常识

数字集成电路是处理数字信号的电子电路,因具有很多优点而被广泛的应用。常用有TTL、CMOS集成电路两大类。本文对使用TTL、CMOS集成电路的一般规则,正确使用方法作了详细介绍。     

InP-based RTD/HEMT monolithic integration

Monolithic integration of resonant tunneling diodes (RTDs) and high electron mobility transistors (HEMTs) is an important development direction of ultra-high speed integrated circuit. A kind of top-RTD and bottom-HEMT material structure is epitaxied on InP substrate through molecular beam epitaxy. Based on wet chemical etching, metal lift-off and air bridge interconnection technology, RTD and HEMT are fabricated simultaneously. The peak-to-valley current ratio of RTD is 7.7 and the peak voltage is 0.33 V at room temperature. The pinch-off voltage is -0.5 V and the current gain cut-frequency is 30 GHz for a 1.0 μm gate length depletion mode HEMT. The two devices are conformable in current magnitude, which is suitable for the construction of various RTD/HEMT monolithic integration logic circuits.     

基于EDA技术的电子信息课程整合教学研究

EDA即电子设计自动化是一种实现电子系统设计自动化的技术,它研究电子设计的全过程.模电、数电和单片机技术是电子信息专业的基础课程,也是学好该专业的重要基石.本文根据目前高校中的课程教学情况和专业发展的要求,提出了一种基于EDA技术的模电、数电和单片机技术的可操作性强的课程整合教学方法,它迎合了当今社会的需求,能极大地提高教学效果和质量.充分挖掘学生潜力,有效培养具有扎实的专业知识的高素质专业人才,对有效地推动高校教育改革和尽快发展也具有重大现实意义.     

模拟电路故障诊断的方法研究

微电子器件的发展趋势是大规模、超大规模集成电路,集成度越来越高,芯片上功能元件的尺寸越来越小。在超大规模集成电路制造技术的推动下,电子电路的处理能力和复杂程度成倍地提高,与现在诊断能力形成了尖锐的矛盾,在这种情况下,大量的科研机构都加入到电路故障诊断的研究中来。本文介绍了模拟电路故障诊断的常规方法和模式识别方法。     

IGBT及其驱动和保护电路的研究

优越的性能使IGBT成为大中电力电子装置首选的功率器件,驱动与保护电路是电路设计中的难点和关键。该文介绍了IGBT的研发新进展,研究了IGBT栅极驱动和保护电路的设计思想,并给出了以EXB840为驱动器的实用电路。研究表明,这种混合驱动集成电路对可靠保护IGBT很有益处。     

Digital Computer Calculation of the Operation of Nonlinear Devices with Energy Storage Elements

This paper presents results on digital computer calculation of the operation of some tube and transistor circuits which combine nonlinear operation with energy storage elements. The Class C amplifier, the frequency multiplier and the blocking oscillator are all circuits of this type. This approach allows many of the conventional restrictions on analysis procedures to be removed. For instance, in the case of the Class C amplifier, it is not necessary to assume that the plate and grid voltages are sinusoidal and the circuit at steady state. Additional features of computer use are the automatic calculation of efficiencies, plotting of waveforms and calculation of harmonic content; the facility of studying the effects of transients and modulation; the possibility of allowing the circuit parameters to take on any values or vary with time or with the voltages and currents; and the possibility of allowing the circuit associated with the device to be more complicated than usually allowed by other methods. Limitations to this approach lie in the cost of programming the problem, and the cost of running the program on an available computer. Questions of numerical accuracy sometimes arise, but can usually be handled with additional programming or running time. If a translator is available which can accept programs in the form of algebraic equations, the programming cost is often negligible. However, running time costs may be appreciable, particularly in the case of a complicated circuit with many storage elements.     

A Microcomputer Interfacing Course for Computer Science Majors

This paper describes a microcomputer interfacing course for computer science students. Students build simple logic circuits to interface a microcomputer with real‐world devices, such as stepper motor and digital displays, and program the computer to monitor and control these devices. Programs are written in Pascal and assembly language. The emphasis is placed on applications rather than on theory. This course is especially designed for computer science students who are proficient in software programming but have little or no experience in electronics. The experiments described here have been developed on the Apple ft microcomputer, but they can be easily adapted to other microcomputers.     

一种基于IR2113的隔离型MOSFET驱动电路设计

以MOSFET作为主要功率开关管,应用于200 V输入的全桥逆变电路中,分析了电路的工作特点及MOSFET驱动电路的设计要求,以及针对开通关断过程所需的电气特性,设计了一种采用光耦隔离、IR2113控制的MOSFET高速驱动电路.实验结果证明了设计的可行性,测试数据和波形该MOSFET驱动电路具有电气隔离性能优良、驱动能力和抗干扰能力强等特点,目前该电路已成功应用在一台逆变器实验样机中,运行稳定.电路设计对IGBT等其他电压控制型功率开关器件的驱动也有一定的借鉴意义.     

相乘器在频率变换技术中的应用

频率变换是无线电通信系统中不可缺少的过程，频率变换是由非线性元件及其组成的电路来实现。相乘器是由非线性元件组成，可以实现两个信号的相乘，完成频率变换的电路。该文从原理上分析了相乘器在频率变换中的应用及过程。     

Using Laboratory Experiments and Circuit Simulation IT Tools in an Undergraduate Course in Analog Electronics

Laboratory-based courses play a significant role in engineering education. Given the role of electronics in engineering and technology, laboratory experiments and circuit simulation IT tools are used in their teaching in several academic institutions. This paper discusses the characteristics and benefits of both methods. The content and structure of an introductory laboratory course in analog electronics is described. The aim of the course is the better understanding of the basic principles of analog electronic circuits without the need of specific technical and computer skills. The impact of the proposed method on the learning process is investigated. The evaluation of our proposal was based on both quantitative and qualitative data. Interesting conclusions about the teaching of electronics in undergraduate education are finally drawn.     

简易的高功率因数电子镇流器

针对目前市场上电子镇流器产品成本偏高、性能不稳定而不利推广的缺点,提出一种研制性价比优良的新型电子镇流器的方法,并阐述其工作原理。指出该类型电子整流器是由一种单级电源电路分别和两种以集成电路555为核心的控制电路结合而成,因而具有电路简单、成本低、功率因数高的特点。     

EDA技术在数字集成电路后端实验教学改革中应用

集成电路技术的飞速发展,对数字集成电路后端课程的教学方法和手段提出新的要求。为适应这种要求,提出将现代电子设计自动化(EDA)技术纳入教学实践全过程的新思路。基于数字集成电路的理论和方法,针对集成电路后端设计及其工程实践课程前期教学存在的不足,通过引入EDA技术的方式对改善课程和实验教学效果进行探讨。近几年的教学实践表明,应用EDA技术对数字集成电路后端实验课程教学进行改革,对激发学生的学习兴趣起到积极作用,同时还可加深学生对基本概念的理解和提高学生集成电路设计的动手能力。     

新型集成电源原理与应用

新型集成电源是—种性能先进,用途广泛的单片集成电路.本文分析了两种典型集成电源的工作原理,并对其应用技术做了详细介绍.     

面向制造的板级电子电路产品多信息模型研究

Most electronics products use PCB to carry electronic circuits. This paper classifies information contained in PCB-based electronic circuits into several models: geometry model, physics model, performance model and function model. Based on this classification, a multi-information model of product is established. A composite model of product is also created based on object-orientation and characteristics of the product. The model includes a 3D geometry model, a physics model with integrated information that can be divided into microscopic and macroscopic information, a generalized performance model and a function model that are from top to bottom. Finally, a multi-unit analysis is briefly discussed.     

A proposal to encourage intuitive learning in a senior-level analogue electronics course

One of the most important issues in the reorganisation of engineering education is to consider new pedagogical techniques to help students develop skills and an adaptive expertise. This expertise consists of being able to recognise the nature of a problem intuitively, and also recognising recurring patterns in different types of problems. In the particular case of analogue electronics, an additional difficulty seems to be that understanding involves both analytic skills and an intuitive grasp of circuit characteristics. This paper presents a proposal to help senior students to think intuitively in order to identify the common issue involved in a group of problems of analogue electronics and build an abstract concept based on, for example, a theory or a mathematical model in order to use it to solve future problems. The preliminary results suggest that this proposal could be useful to promote intuitive reasoning in analogue electronics courses. The experience would later be useful to graduates in analytically solving new types of problems or in designing new electronic circuits.     

SMT中焊膏使用常见问题分析

SMT是现代电子产品追求小型化,特别是大规模、高集成电路(IC),不得不采用的一项组装技术.作为新兴技术,在实际应用中总存在一些问题,就其使用的焊锡膏在实际应用中出现的问题进行了分析,供从事SMT人员借鉴.     

一种漫反射式光电开关的实现

介绍了一种漫反射式光电开关电路,为了获得较大的探测范围,利用555电路产生1．5KHz调制脉冲和35kHz载频脉冲,接收回路采用集成锁相环路解码器,确保了电路的抗干扰能力,经调试达到了设计要求。