热释电红外探测器的OTA整流电路优化设计

本文提出了一种可用于热释电红外探测技术的基于跨导运算放大器(OTA)且唯一有源器件的全波整流电路,该电路利用OTA的差分放大特性,明显改善了普通运放整流电路引起的输出波形过零失真。针对普通OTA输入信号范围小的缺点,提出补偿OTA全波整流电路,不仅扩大了输入信号范围,同时通过调节偏置电流可实现整流后信号再次放大。给出了仿真结果并用于大信号宽频带热释电红外探测电路,实验证明电路工作稳定,整流输出达到预期效果。     

用伴测电路提高电测系统的准确度

本文论述了伴测电路在电测系统中的应用。对电测系统中的若干点附加伴测电路,可以提高系统的测量准确度。例如在不降低稳定性的基础上,克服直流或交流运算放大器因有效开环增益不足而引起的运算误差,并消除相应输出电路的负载效应。此电路原理还可应用于标准电源和精密电表的校验。     

激波压力传感器信号处理电路设计

针对声学靶装置中采用的一种激波传感器．设计了相应的传感器输出信号转换、处理电路,该信号处理电路由电荷放大电路和滤波电路组成。采用运算放大器OPA604设计了电荷放大电路,信号滤波电路采用集成有源滤波器UAF42进行设计。经实弹测试验证,利用该信号处理电路,得到了较好的弹丸激波压力波形。     

谈EC—8型接地电阻测量仪的检修

接地电阻测量仪是属于国家计量局颁的强制检定工作计量器具之列,其检定周期一般为一年。为了方便检修,特对 EC—8型接地电阻测量仪的检修以及相敏整流电路原理作一介绍供使用、维修、检定人员参考。一、相敏整流电路原理分析EC—8型接地电阻测量仪电路如图1所示,其输入、输出、解调电压波形如图2所示。当被解调电压 e(波形如图2中 a)与交流输入信号 U。 (波形如图2中 b)同相时,     

电涡流传感器测量电路的设计与仿真

本文介绍了电涡流传感器的基本原理、基本结构以及电涡流传感器的各种配用电路,详细分析并设计了定频调幅式测量电路。该测量电路主要包括正弦波激励源环节、调幅电路、整流滤波以及峰值检测环节。通过Multisim仿真,得出相关位置的波形图,由波形可得出该测量电路具有响应速度快、稳定性高、适应性广等特点。     

铂热电阻测温电路实用性的探讨

针对热电厂常用电阻测温电路,将电阻值转换成相应的电压信号,采用三导线单臂电桥,放大电路部分采用了精密放大器的放大电路,新设计的电路系统在0-630℃范围内具有较小的误差,测量精度较高。     

提高稳定性的电路联结法

提高稳定性的电路联结法典型的测量放大器电路如图１，是用三个运算放大器构成的。其放大倍数是通过电阻ＲＧ来调整。放大器的差动输入端＋ＩＮ和－ＩＮ分别是两个运算放大器Ａ１和Ａ２的同相输入端，因此输入阻抗很高，且采用对称电路结构，被测信号直接加入到输入端上，...     

电子管扩音机产生交流声的原因及检修方法

扩音机产生交流声故障的原因 1．直流高压整流电路中，整流管半边损坏或电源变压器半边绕组断路，使全波整流变成半波整流，直流输出电压纹波增大。     

运算放大器在矩形和三角波形方面的运用

针对机电专业学生对数字电路运算放大器在波形方面的运用比较困难，特别是对电路能进行分析和计算得出波形难以下手，我从典型的基本电路人手，分析电路，计算电路，最后画出波形图都做了详细的论证。     

高精度小电流恒流源的设计与实现

目前以TL431稳压管搭建的恒流源电路存在小电流输出状态下输出精度较低,温度跨度大时工作电路的温漂较大,且不具备抑制温漂能力,在飞行器系统测试过程中无法全面地满足指标需求。该文对TL431恒流源做出改进,加入精密运算放大器OP77及π型滤波电路以保证输出精度,设计温度系数互补的电阻网络,通过调整合适的补偿点降低恒流源整体温漂。实验结果表明:改进后恒流源具有低温漂、高精度的优越性能。     

Digitally programmable active-R square wave generator

A digitally programmable active-R square-wave generator circuit is discussed. The circuit uses only two operational amplifiers, two operational transconductance amplifiers, and resistors. The main features of the circuit are the following: it uses only resistors without recourse to any external capacitors. Therefore, it is attractive for monolithic implementation. It can be used with any mini/microcomputer or microprocessor-based system. It is possible to obtain a linear relationship between the control voltage and the frequency of oscillation. Experimental results are presented     

Highly productive sorting of resistors

Conclusions The above circuit was successfully used for mass-production sorting of plug-in resistors with nominal values from 10 to 9000 ohm used in a universal network model.Reference resistors of the sorted nominal values are incorporated in the circuit for the convenience of operation. The set is universal and can be used both for measuring resistors and for their sorting with high precision. The resistors are sorted at a rate not exceeding 3 sec per resistor. The circuit can be recommended for use in automatic sorting machines.     

The Accuracy of Series and Parallel Connections of Four-Terminal Resistors

The range and accuracy of resistance calibration can be increased by the use of series and parallel connections of four-terminal resistors. Low value resistors can be permanently connected in series and reconnected in parallel by using Hamon's1 technique to change resistance level without materially affecting resistance accuracy. The resistors are connected in parallel by attaching shorting bars to one terminal at each end of each resistor and attaching matched resistors in series with the other terminals. High accuracy can be attained even though lead and connection resistance are relatively high. The purpose of this paper is to provide a theoretical base and an error analysis to justify the use of the series-to-parallel transfer technique at low resistance levels. The analysis uses a four-terminal equivalent circuit suggested by Searle.2 The accuracy of series and parallel connections of groups of like resistors is investigated in terms of the equivalent circuit. Procedures are developed for determining the connection accuracy of a set of resistors in parallel or series.     

Sinusoidal frequency doublers using operational amplifiers

A simple sinusoidal frequency-doubling circuit is proposed which incorporates operational amplifiers (op amps) with resistors as the only external components. The realization method makes use of the inherent translinear loop at the input stage of the op amp as a means to perform frequency doubling. The response of the circuit is discussed and experimentally demonstrated     

JFET Circuit Linearizes Transducer Output

A circuit employing one operational amplifier, one dualjunction field-effect transistor, four resistors, and two potentiometers is used to produce a voltage output proportional to the quantity t when the input voltage is related to t by at + bt2, where a and b are constants. The useful operating voltage range, the maximum value of bt/a that can be accommodated, the accuracy of the linearizing process, and the effects of changes in the ambient temperature on the circuit are considered.     

A novel noninverting VCVS with reduced magnitude and phase errors[voltage-controlled voltage sources]

A novel noninverting VCVS structure comprising three general purpose operational amplifiers (OAs) and four passive resistors is described. Its usefulness in extending the range of maximally flat magnitude and phase responses was investigated in depth. The effect of the second pole of the OA on the circuit stability has also been presented. The proposed design has the advantage of flat magnitude and phase responses over an extended frequency range     

Current Conveyor-Based Square/Triangular Waveform Generators With Improved Linearity

Two second-generation current conveyor (CCII+)-based resistance–capacitance $(RC)$ square/triangular waveform generators, which have been derived from their voltage-mode op-amp-based schemes, with independent control of frequency are presented in this paper. Each configuration consists of two positive second-generation conveyors (CCII(+)-“A” and CCII(+)-“B”), three resistors, and one floating capacitor that is responsible for better linearity. The frequency of the waveform generators can independently be adjusted with any passive device. The circuits were built with commercially available current feedback operational amplifiers (AD844) and passive components used externally and tested for waveform generation and tunability. The measured results included in the paper show excellent linear variation of frequency as compared with existing reported configurations over the range from 25 Hz to 260 kHz. The configurations that are suitable for very large scale integration (VLSI) realization find application in capacitive and resistive sensors and in neuro-fuzzy systems.      

数字式频率与波形合成技术及其应用

介绍了实现变频陀螺电源高频率稳定度和高输出波形精度的关键技术——数字式频率合成技术和数字式波形合成技术——的原理 ,并给出了设计电路和测试指标。     

在线电阻测量仪电路

本文提出了一种在线电阻测量电路。这种电路具有等电位隔离特性,能消除电网络中其它电阻对被测电阻的影响,可实现网络电阻的直接测量。文中对误差进行了分析,给出了实验结果。