An op-amp (operational amplifier) is a high gain analog voltage amplifier with differential high impedance inputs, and a low impedance output. A basic building block in signal processing, like as amplifier or active filter.

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Dual Digital Pot With Different Op amps & Layout

I'm using a dual digital pot IC controlled with an SPI interface. Each pot goes to a different op amp on the pcb to calibrate two different voltages. Since both pots are in the same package, how big ...
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61 views

OP amp PI controlled electrical load

I am building an electrical load, capable of "sinking" 0 - 3A on a maximum of 60VDC. I want to control the load with a microcontrollers ADC (0-3V). On the internet you find hundereds of circuit ...
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49 views

How to chose the right decoupling/bypass capacitor variant for opAmp power rails?

Many experts here recommend 100nF bypass caps to the power rails of an opAmp. So I made it a tradition myself that when I use any opAmp I always use 100nF decoupling cap from +Vcc to GND and -Vcc to ...
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63 views

voltage controlled oscillator

Given below is a VCO circuit. Can anyone explain how the components work (especially the resistors and capacitors) and why the resistor and capacitor values are selected so. and what are the values to ...
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57 views

Unexpected results when trying to amplify voltage across a wheatstone bridge

I am working on a project, and am trying to amplify the voltage across wheatstone bridge. Here is the diagram: where \$R_1 = 1,000 \Omega\$ \$R_3 = 10,000 \Omega\$ and \$R_2\$ is a ...
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34 views

Voltage follower with LF411 shows -6dB instead of 0dB

I designed the circuit shown in the first picture. It is a voltage follower realised with a LF411, connected to its output is a load of 10k and an AC source on its input with an amplitude 0.5V. I am ...
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40 views

Calculating voltage on inverting and non inverting pins for an op amp

How does he calculate Va and Vb here: I understand the rest of the stuff after he figures out what Va and Vb are. But how do I figure out Va and Vb when not given the values ->
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71 views

Design of audio playback system

I'm having trouble understanding some concepts: In a complete audio playback system the out put of the DAC is connected directly to the input of the low-pass filter, and the output of the low-pass ...
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33 views

How are the circuits and design considerations for opamps and comparators different, at an integrated transistor level?

I've designed various transconductance and operational amplifiers in CMOS technologies in the past. I've also worked with clocked latching comparators. However, I've yet to design an asynchronous ...
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15 views

ECG Signal Measurement using Plessey PS25201

The above said sensor measures the change in the electric field. Data sheet link : Click here When I measure the output from the sensors directly on the CRO with finger placed on the sensor; the ...
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2answers
79 views

Can I connect pin 11 of TL084 to ground? I mean, are there the consequences?

I wonder if it is possible to connect pin 11 of a TL084 to ground to avoid having two sources. I need to compare two signals: Signal 1: This is a DC 9V source. (this goes to + terminal of Opamp) ...
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54 views

Designing an High Amperage, Low Voltage AC Voltage “Breaker” for Model Train

I’m trying to build a simple circuit that acts as a "voltage breaker" – meaning that if a voltage exceeds a certain threshold, analogous to a (current) circuit breaker it will open a circuit. There ...
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26 views

charge sensitive amplifier

I am testing ORTEC 142A preamplifier. Its a charge sensitive preamplifier. I am very confused with some terms. what is open loop gain? what is mean by that? For ORTEC 142A open loop gain >40,000 and I ...
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32 views

Sharp and Simple Analog Filter suggestions

I'm looking for schematics of some simple opamp-based analog filter, which has a sharp band-pass functionality. I want it to control small robot with sounds of different pitch. The matter is like ...
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2answers
62 views

What is the most efficient way to prevent reverse polarity to an opAmp?

Above is a part of a circuit which is a Schmitt trigger. As you see 24V DC Vcc and Gnd are the power rails. I will set up this circuit and some other people are going to hook up input output and ...
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74 views

what is the maximum output voltage from an opamp in general case?

In general, what is the output voltage that an amplifier (not rail-to-rail output type) can provide,if it is supplied for example Vdd=+24V and Vee=-24V which is the maximum value I can get "for sure" ...
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56 views

LM358 (as comparator) output voltage less than supply voltage

I've setup a simple circuit with an LM358 configured as a comparator (the ground rail and supply connections are off screen). Schematic: Breadboard: (in case I wired something wrong) Measured ...
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208 views

Why do audio op amps require such high rail voltages?

This might be a silly question, but I haven't been able to find it addressed directly anywhere on the internet yet. I also have a handful of related questions in-line, which I hope don't stray too ...
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70 views

Why does my op-amp circuit always give near zero output?

I have an op-amp design same with the picture seen below with TLC271.I have an analog sensor that goes as Vin. I am giving 3.3V from an arduino to power it. And reading values from an analog pin. The ...
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91 views

Using op amp to measure battery voltage

I have a question regarding the usage of op amp to measure battery voltage. I know there are battery gauge IC's dedicated for that, but I'm trying to do this to both understand the op amps better and ...
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31 views

OP-Amp LM124 IC current problem

I am using lm124 op-amp IC in my circuit. 3 of 4 op-amp are being used as voltage followers while one op-amp is being used as comparator. The IC is drawing 23mA current at 8.6V supply. Kindly help me ...
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64 views

Opto-coupled PWM

Following on from this question: I have the task of setting a voltage V_set using PWM. The challenge arises from the fact, that V_set is referenced to a different ground than the MCU. My currently ...
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3answers
98 views

Can opamps marked as single supply be driven from a dual supply?

Can an opamp designated as a single supply opamp be driven from +/- dual supplies as long as its within the VDD - VSS range? I'm looking at this particular opamp from Microchip.
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118 views

How to change the range of a potentiometer

How to change the range of a potentiometer from 10-90 Ohms to 0.5- 4 Ohms using an operational amplifier
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86 views

Confused about Op Amp

So in the linear operating range of an op amp the output is A(Vp-Vn) where Vp is the voltage at the positive terminal and Vn is the voltage at the negative terminal. But that does not seem to always ...
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33 views

Alternative to using the LM272 for driving a DC motor

In this instructable, the LM 272 is being used for driving a simple dc motor. My friends and I are trying to use the same concept for our project(which is similar in nature), however there are only ...
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54 views

Amplifiers: Periodic and non-periodic signals

All the signal amplifiers (op amps) I've dealt with thus far use periodic signals. The idea of bandwidth is natural when dealing with these periodic signals because it is just a description of the ...
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65 views

Sound pressure to db analog

I'm trying to convert an amplified microphone output (it is from 0-5v, biased at 2.5v) to a linear response that correlates with db SPL. From my research, the output of the microphone directly ...
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1answer
93 views

Purpose of this Resistor in Circuit attached

What is the purpose of resistor (R2, 33ohm) in the circuit below? Q) is it for current limiting , if So the current can go 15V/33ohm = 454mA, but opamp can not give this much current , most opamp ...
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88 views

Can you help me solve this op amp? [closed]

What type is this Op amp? What is formula for calculating Vo.
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42 views

Are the terms corner frequency,cutoff frequency and break frequency the same?

I am studying electronics engineering and I came across these terms..how are these terms different from each other?
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63 views

Why does bringing TL072/TL074 non-inverting input low cause output to go high?

I was building a circuit using a Texas Instruments TL074 as a comparator, when I noticed some strange behavior. I isolated the chip and tested it with a couple of potentiometers. Basically, when I put ...
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136 views

Is there a technical reason why you might use a two inverting amplifiers instead of a single non-inverting amplifier?

For example, I found a schematic that uses two inverting opamps to amplify the output of an AD590 with a gain of 1000: In this case the second opamp appears to be doing nothing but "re-inverting" ...
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30 views

Design of the two stage amplifier with p-type input

I have to design the two stage amplifier with p-type input (p-type diff pair), the schematic bellow: However, mostly tutorials discuss the same architecture but with n-type input. My main ...
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61 views

Difference between an ideal integrator and a practical one

I only learned about the ideal integrator design (top circuit), but when I searched for a practical model for an integrator I found it was like the one in the bottom circuit. Two new elements, Rf and ...
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37 views

Obtain transfer function of op amp circuit

I'm trying to find the transference function H(s) of the next op-amp circuit: I get the next following equations: When I put the equations together, this is an absurd. How do I solve this?
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How to construct High Speed Log Amplifiers

Objective : converting laser pulses from photo diode ranging from 10nA - 100mA (60dB dynamic range of incident power) to digital format, for measuring pulse width exactly pulse width 10ns and ...
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31 views

can ct sensors share a common fixed reference point?

In a previous question, I asked how to amplify a CT sensor, essentially a small transformer that induces a voltage proportional to the current in the primary circuit. The solution has one leg attached ...
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38 views

Differential to Single-ended conversion clipping issue

I am attempting to convert the differential output of a DAC to a single-ended signal using the following circuit from a TI datasheet: The signals going into this amplifier look like this: And ...
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3answers
160 views

Why does my op-amp circuit always give the same output?

I have an op-amp design same with the picture seen below with TL072.I have an analog sensor that goes as Vin. I am giving 3.3V from an arduino to power it. And reading values from an analog pin. The ...
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1answer
51 views

how to twin-t notch filter topology single supply opamp

i designed for twin-t for 50 Hz and BW=2 I have to use single supply opamp but i cant get it single supply opamp thing ... Can anyone tell me which node i have to do ground , which node i have to ...
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106 views

Difference between LM741CP and LM741CN? [closed]

simulate this circuit – Schematic created using CircuitLab I'm having an analog project where I have to amplify a weak signal coming out of a photo transistor. I used LM741CN OpAmp for ...
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1answer
46 views

Bridge circuit and the error caused by a differential amplifier

I am currently struggeling with solving the following problem: The circuit below shows a bridge circuit, where the differential voltage between the branches is measured by a differential amplifier. I ...
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18 views

Different Op Amp output for battery/usb power

I'm using a micro running arduino to measure the resistance between two electrodes, connected to a dual op amp with automatic feedback control bias. The output is accurate when the circuit is powered ...
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1answer
57 views

Why this high-pass filter behaves like a low-pass filter for high frequencies, on this ideal LTSpice simulation?

I am simulating the usual active, first-order high-pass filter on LTSpice, as below: The Op-Amp I'm using is the following: This is the simulation result: What is the explanation for the ...
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5answers
73 views

OpAmp used as adder

Let's say this operational amplifier, wired as adder, is given. Since the ideal OpAmp has an infinite input impedance, there won't be any current flow in the (-)-input. How can I calculate the ...
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3answers
108 views

How to make perfboard circuits more compact

So, I've been working on my prosthetic limb for quite some time, and I've sorta bumped into a few problems, while the circuits I've made work, they don't fit inside the arm. Mostly because I have tons ...
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100 views

Where does an op amp's input bias current come from if capacitor is used?

In the case of a non-inverting amplifier, if I DC couple the input signal with a capacitor only, \$C_1\$ (i.e. no resistor to ground), sources (as well as an experiment in the lab) show me that the op ...
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31 views

Dual power supply for the LMV324M

This smartplug reference from TI makes use of a LMV324M for the metrology bit, which is the low power version of the popular LM324. Its being powered from a +/-3.3V supply in the design however the ...
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How does op-amp gain = 1 - error?

Please see attached image. How does the voltage gain end up being equivalent to Av = 1-error? Thanks