Operating principle of dual collector magnetotransistors studied bytwo-dimensional simulation

Dual collector magnetotransistors are magnetic-field-sensitive devices currently developed in several laboratories. Optimized sensor design is often attempted by trial and error rather than by established design rules. This motivated the present comprehensive study of the operation of magnetotransistors by accurate two-dimensional numerical simulations. We model vertical and lateral transistors as obtained by industrial IC technology on the basis of data provided by the chip manufacturer. We consider the entire device structure with the full, complex device geometry, and the physically proper boundary conditions. Our simulations reveal the details, controversial hitherto, of the operating principle of these devices. In particular we find that, in the case of the vertical transistor, it is essentially the emitter injection modulation effect which dominates the sensor response. In the case of the lateral transistor, the magnetic sensitivity is predominantly determined by minority-carrier deflection, though side effects are involved as well. By variation of the doping profile and the device geometry we derive rules for optimized magnetotransistor design     

一种小型智能漏电保护器的工作原理

本文介绍一种在供电系统中适用的小型智能漏电保护器的功能和特点，分析了电路各部分的工作原理。     

VM提高图像质量的工作机理

首先介绍了ＰＡＬ－Ｄ的图像分解力和均匀电子束屏迹计算方法,而后对ＶＭ的工作原理,ＶＭ电流速率的选择及人眼的清晰度感觉重点作了叙述。     

Analysis of distributed feedback semiconductor lasers bytwo-dimensional theory

The two-dimensional theory of distributed feedback (DFB) lasers to take account of the planar waveguide structure which was presented in a previous paper (see ibid., vol.26, no.3, p.467-72, 1990) is applied to the analysis of the DFB laser threshold conditions with respect to the effects of the waveguide structure and the facet reflection. The asymmetric properties of the transverse functions of the coupled modes with respect to the Bragg frequency in the dispersion relations are found to be enhanced by the asymmetric index waveguide structure and by the asymmetric facet reflectivity. Therefore, the resulting confinement factor differences in the grating layer between the two adjacent lasing modes on both sides of the Bragg frequency give large threshold gain differences     

An investigation of the sensitivity of lateral magnetotransistors

An investigation of the magnetic-field sensitivity of lateral, double base contact p-n-p magnetotransistor is reported. At very low collector current levels the sensitivity is an exponential function of the base current and rises up to 30 A/A.T at 1 T. At larger collector currents sensitivity decreases drastically and approaches the usual value of less then 1.5 A/A.T. This behaviour is explained in terms of a Hall-type voltage, which is generated in the base region and causes a magnetic-field-modulated injection of carriers.     

NCP1601型功率因数校正控制器的原理及应用

NCP1601型功率因数校正控制器可工作在不连续传导模式（DCM）和临界传导模式（CRM）二种工作模式下.文中介绍NCP1601的结构和特点,详细叙述其工作原理并给出一种典型应用电路.     

Offset in CMOS magnetotransistors. I. Analysis of causes

Fabrication imperfections cause offset in CMOS magnetotransistors (MTs). In this paper, MT offset is experimentally characterized and its causes are analyzed for two different commercial CMOS processes. For the MT structures chosen as references, the average absolute value of the offset in terms of a relative imbalance of two collector currents is up to 2.7%. The mean offset temperature drift between -40°C and +140°C is 0.25%. The offset exhibits a high degree of variation on a very small spatial scale. Additionally, variations on a large scale over the wafer are observed and, in some cases, systematic influences. The actual offset contributions of the various identified possible sources are investigated. Misalignment of the metal contact mask occurring during photolithography dominates large scale offset variations and can also have a systematic component. Another systematic influence arises from nonorthogonal dopant implantation. Doping inhomogeneities are a dominating contribution to local variations as indirect evidence suggests. Further, mismatch in emitter-collector spacing is critical. Suppressed sidewall injection magnetotransistors (SSIMTs) showing an enhanced sensitivity exhibit a quadrupling of the offset, which comes from a misalignment of the emitter guard ring. The obtained results are the basis for dedicated offset reduction in MTs as well as the development of MT-like test structures for processing tolerances     

Extension of on-surface radiation condition theory to scattering bytwo-dimensional homogeneous dielectric objects

A recent analytical formulation by G.A. Kriegsmann et al. (see ibid., vol.AP-35, p.153-61, Feb. 1987) of electromagnetic wave scattering by perfectly conducting two-dimensional objects using the on-surface radiation boundary condition approach is extended to the case of two-dimensional homogeneous convex dielectric objects. It is shown that a substantial simplification in the analysis can be obtained by applying the outgoing radiation boundary condition on the surface of the object. The analysis procedure decouples the fields in the two regions to yield explicitly a differential equation relationship between the external incident field excitation and the corresponding field distribution in the interior of the dielectric object. The interior fields can be obtained by solving the differential equation using either an analytical approach or a suitable numerical method. Two-dimensional scattering examples along with validations are reported, showing the near-surface field distributions for a homogeneous circular dielectric cylinder and an elliptic dielectric cylinder, with with transverse magnetic plane-wave excitation     

中波调幅发射机工作原理MATLAB仿真

MATLAB是一个很好的科研教学和工程应用仿真软件,它将可视化的方框图模型与编程形式的仿真模型综合起来加以利用。本文利用MATLAB实现对中波调幅发射机工作原理进行仿真。从系统建模原理和仿真的数值计算方法入手,对发射机理论研究、性能分析验证等方面为值机员提供深刻的从量到质的认识机会。     

Staggered-lineup heterojunctions as sources of tunable below-gap radiation: Operating principle and semiconductor selection

Heterojunctions in which both the conduction and the valence band edges of one semiconductor are shifted upward relative to those of the other, can exhibit adjacent dual quantum wells for electrons and holes on the two sides of the interface. Tunneling-assisted radiative recombination between the wells should be an efficient, bias-tunable source of radiation at below-gap quantum energies. Several semiconductor combinations that exhibit the proper lineup are available.     

Effect of nonlinear collector capacitance on collector current rise time

The collector capacity, C, of a junction transistor is known to vary as a nonlinear function of the voltage, V, across it. A calculation is made of the collector current rise time of a grounded emitter alloy junction transistor for which C = kV^-1/2. A comparison is then made with linear analyses in which C is assumed to have one of the following constant values. 1) C = Ccc, where Cccis the small signal capacity measured at the collector supply voltage, Vcc. 2) C = 1.52Ccc. This capacity is one which displaces the same charge as the nonlinear capacity as the voltage across it changes from 0-90 per cent of its final value. 3) C - 2Ccc. This capacity is one which displaces the same charge as the nonlinear capacity as the voltage across it changes from 0-100 per cent of its final value. The linear analysis using the latter two capacity values gives 0-90 per cent and 0-100 per cent rise times which are very close to those given by a numerical solution of the nonlinear circuit equation. The usual linear analysis using C = Ccc, on the other hand, is very much in error for predicting rise time. Experimental results show that the 2Cccvalue, in a linear analysis, predicts the 0-100 per cent rise time almost exactly. In addition, analog computer solutions of the nonlinear circuit equation give results almost identical with the shape of the experimental curves.     

Effect of collector voltage and collector current on junction temperature

Experiments have been carried out on the 2N929 transistor to investigate the effect of collector voltage and collector current on junction temperature. The results indicate that at constant power dissipation increasing the collector voltage will increase the junction temperature and give the apparent effect of a higher thermal resistance.     

数字式双混频时差测量仪原理分析与仿真

为了突破传统时频测量技术的局限性,提高频率稳定度的精确程度,研究设计了一套数字式双混频时差测量系统,采用经典双混频时差测量原理,运用数字信号处理技术实现频标的比对测量。仿真结果证明,采用10 MHz信号进行测量时,得到相位噪声Allan方差优于3E-13/s,可对高精度频标进行实时测量和监控。     

Analysis of highly doped collector transistors by usingtwo-dimensional process/device simulation and its application of ECLcircuits

A report is presented of the results of an investigation of device parameters and collector-to-emitter breakdown voltages of double polysilicon self-aligned transistors with highly doped collectors using a two-dimensional process/device simulation system. Favourable phosphorous-ion implanting condition for a highly doped pedestal collector was found to achieve a high cutoff frequency as well as low AC base resistance and small base-collector capacitance, thereby keeping the minimum collector-to-emitter breakdown voltage of 3 V. The authors also report ECL circuit performance improvements achieved in experiments that realized a minimum ECL gate delay time of 26.3 ps/gate at switching current of 1.64 mA as a result of process optimization. Moreover, a 1/8 static frequency divider T-F/F has been observed to operate up to a maximum frequency of 15.8 GHz     

Operating a three-phase diode rectifier with a low-input currentdistortion using a series-connected dual boost converter

This paper describes a technique for shaping the input current to a three-phase diode rectifier using a two-switch series-connected dual boost converter and a three-phase bidirectional switch circuit. Circuits are described for generating a single voltage DC output, “single DC-rail”, or a dual output DC voltage using center-tapped capacitors, “split DC-rail”. Both rectifier types can be operated with the boost inductors located either on the DC or the AC side of the rectifier. The resultant rectifier circuit configurations have an excellent immunity to the “shoot-through” fault condition and use active switching elements with low per-unit current ratings and low switching losses. These features increase the reliability factor and lower the cost penalty associated with unity fundamental power factor three-phase rectifiers. Test results are presented for the rectifiers using simulation and experimental results     

无透镜激光电线测径仪的测量计算原理及仿真

讨论无透镜系统测量原理的测径方法，建立了测量系统的几何光学模型，得到线径计算公式。通过实验计算程序，分析了线芯直径和位置偏差对测径公式误差的影响，并给出了相应的修正公式。     

速率陀螺式激光导引头稳定跟踪原理分析与仿真

激光导引头是激光末制导武器(炮弹、炸弹和导弹)的核心部件,其性能优劣直接影响对目标的捕获、跟踪性能及命中精度,采用计算机仿真技术对激光导引头系统进行建模和仿真是一条有效评估其性能的途径.结合某速率陀螺稳定式激光导引头的结构特点,研究其空间稳定和跟踪的工作机理,并应用多体力学和空间飞行原理建立了该型导引头伺服系统的数学模...     

基于VB6.0平台的数控原理插补算法模拟软件

讨论了如何用VB(VISUALBASIC)技术实现数控原理插补算法模拟,并对插补算法与VB应用升级有关的问题作了详尽的论述。     

Tunable FSS simulation using WCIP method for multiband and dual polarized applications

A novel multiband-operating and dual polarization frequency selective surface (FSS) for radomes applications for radar stealth is proposed. The design is based on an open metallic ring with coupled end strips. The proposed FSS rejects electromagnetic waves at frequencies 9.1, 10.8 and 11.5 GHz simultaneously with bandwidths of 900, 100 and 200 MHz, respectively, when the structure is excited by the x-polarized plane wave, and it rejects at one frequency 7.3 GHz with bandwidth of 1000 MHz, when the structure is excited by the y-polarized plane wave. Frequency tenability is provided by varying the length of the FSS coupled strips and the left edge of vertical U-shaped metallic strip composing the FSS structure. An enhancement of the x-polarized FSS bandwidth from 900 to 1500 MHz and from 200 and 100 to 500 MHz has been achieved. Simulation results obtained by the WCIP method were compared with the simulation results obtained by the COMSOL multiphysics software 4.3b and with the measurements. A good agreement of the results was observed.