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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613 views

Can I use an op-amp to supply itself a negative voltage?

For my project, I am using an LM324. According to the datasheet, its power supply can either be +/- 16V or 0-32V (max). The output will range from -3V to +3V (or there abouts), so I realise I'm going ...
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1answer
40 views

Filter Based Projects using op-amp [on hold]

I have been given a task to make a small filter based project using operational amplifier(s). I can't figure out any good ideas to choose a circuit. Any suggestions which project should I choose?
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1answer
32 views

summing amplifier

The purpose of this lab is to find the gain voltage of op amp. I used multisim to plot it, but I get a constant voltage for Vout as appose to inverted signal. could you please have a look it and let ...
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3answers
276 views

Differentiator circuit - can output be larger than input?

I have a question regarding differentiator circuits, and whether or not their output voltage can be greater than their input voltage. The voltage across the resistor in such a circuit corresponds to ...
0
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2answers
29 views

ATmega32 withRC filter and OpAmp

In my circuit (picture below), ATMEGA32 output is connected to a RC filter (R=100K, C=10uF 63V) to non-inverting terminal of OpAmp (LT1006). OpAmp is configured as voltage follower (Buffer Amplifier). ...
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1answer
15 views

Buck Converter Error Amplifier Input Polarity Confusion (TL598)

I'm trying to design a buck converter using TL598. I'm studying the technical article Designing Switch Mode Power Supplies With the TL598 - Application Report for this purpose. This article references ...
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0answers
27 views

From RLC prototype to signal flow graph

This simple 3rd order low-pass circuit simulate this circuit – Schematic created using CircuitLab can be described with the following 3 equations: $$-V_1 = \displaystyle \frac{-1}{sC_1} ...
3
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3answers
225 views

How to prevent op amp from saturating?

How can an op amp be prevented from going into saturation if the feedback is intermittently disconnected? For example, in this circuit (simplified case of a real-life problem), the op amp acts as a ...
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2answers
74 views

Current limiter its not working as it should?

I have created a voltage regulation circuit using op amp and feedback resistors, now I am trying to add a current limiter to the circuit. have read how to create this using two transistors and a ...
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1answer
65 views

Voltage follower

I designed the circuit , but I don't understand part e). how can I use voltage follower in these two circuits ?
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1answer
71 views

Tactics for stable unity-gain op-amp

The circuit given below is typical pH meter op-amp circuit. But here LMC6001 is not configured as unity gain. My question is this, I want to make this circuit with unity-gain buffer op-amp. What ...
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0answers
116 views

Magnetic Levitation

I am new to electronics, and I want to do a project where I make a device that levitates an object with the use of an electromagnet, for learning purposes. Something like this is what I had in mind: ...
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2answers
50 views

How to calculate the amplitude of a Wien Bridge Oscillator?

How do I calculate the amplitude of the waveform that is created with this Wien Bridge Oscillator? My scope measurement shows 1V. My LTSpice shows ~.8V. Thank you.
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4answers
266 views
+200

Determining amplitude of a 2 MHz sine wave

I'm designing a class E resonant inverter at a switching frequency of approx. 2 MHz. I need to control the inverter so as to maintain a constant current at the load. My strategy would be to put a ...
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1answer
41 views

What should be the output voltage for Virtual Ground to occur in Inverting OpAmps?

If I give 1v as an input to this inverting opamp, the output should be -10v just to make the difference between the input terminals 0. But when I solve the circuit using KCL for 1 volt input I get ...
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2answers
89 views

How to create this opamp circuit for mind machine

I'm trying to create a circuit to blink lights at the precise frequency for a mind machine. The lights need to be in sync with audio. Audio channel 1 300 hz Audio channel 2 310 hz The led needs to ...
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1answer
87 views

Why use two power sources when designing a voltage regulator using a zener diode

I am currently designing a voltage regulator using a 5V zener diode. I am wondering why some people choose to use two power sources instead of one, what would be the benefits of this ? the circuit ...
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2answers
44 views

Flash ADC with TL074 & 74LS148: encoder inputs always high?

I am attempting to build a 3-bit 0-5V flash ADC using two TL074 quad op amps and a 74LS148 active-low priority encoder. The circuit is fairly simple. 8 100K resistors are connected in series between ...
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3answers
135 views

Op-Amps with unequal split supplies (e.g. V+ = 25V, V- = -11V)

Most electronic designers will be familair with designing op-amp circuits with a single supply rail (e.g. Vs+ = 5V, Vs- = 0V) or matched split supplies (e.g. Vs = +18V, Vs- = -18V). I have a design ...
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3answers
94 views

Can someone explain this gain & offset op-amp circuit?

I'm having trouble understanding the circuit in the photo below. I know that it's a gain and offset amp designed to convert 0-2.5 V range to +/-10 V range (hence it has a gain of 8 and an offset of ...
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3answers
206 views

Transform a 0-10V into 0-5V and use op-amps as buffers?

I would like to transform a 0-10V into a 0-5V so I can read it with "5V MCU" (like the AVR/Arduinos). In the most basic case I would just put 2 resistors and do a divider, but since I don't know how ...
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2answers
84 views

Op amp circuit design

I am having trouble with understanding how to design circuits involving op amps. I need to design a circuit using as less op amps as possible which has the following characteristics: high input ...
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3answers
297 views

What is the purpose of a resistor on the non-inverting terminal of an Op-Amp Integrator? [duplicate]

I have seen this type of circuit design a few times, but am not sure why it is needed. Considering the schematic below, what is the purpose of resistor R3?
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4answers
298 views

Switching resistances in op-amp amplifier

I am building an inverting amplifier with an op-amp to attenuate a signal (ie: gain < 1) and I would like to be able to change the gain electronically by connecting multiple resistors to a switch ...
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4answers
85 views

Does the op-amp output depend on the difference in input?

If there's two different input voltages, does the op-amp amplify the difference between them. Or is it only the differential op-amp that does this ? I'm confused!! .. I remember a question where the ...
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1answer
90 views

what does this OPAMP circuit do (with parallel diode and resistor)

It kinda looks like schmitt trigger but i couldn't understand the parallel diode resistor part. Is it possible to analyse this circuit with node-voltage method?
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3answers
151 views

Why is a gyrator negative feedback?

Consider this circuit, this is a gyrator and acts like an inductor. Why when we analysis this circuit do we use assume negative feedback (i.e. the voltage at each input is the same). I thought that ...
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1answer
59 views

interference proof voltage regulated current source

I want to dim some LEDs, using the PWM output from a microcontroller. There are some more LEDs than in the schematic, already wired, so that they need nearly 12 V to give maximum light at about 50 mA. ...
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1answer
64 views

Non-inverting amp Gain

I am making a differential amp with a non-inverting amp with a gain of 4.9 with the use of an AD822 http://www.analog.com/static/imported-files/data_sheets/AD822.pdf which is a dual rail-to-rail op ...
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1answer
57 views

how to calculate the current in this circuit ( opamp)

how to calculate the current in this circuit (show with the green arrow) Can someone explain with a bit of details. In the books i got from school, they dont come close to what this looks like.
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2answers
55 views

Thevenin Equivalent circuit for T feedback network of inverting ideal op amp

simulate this circuit – Schematic created using CircuitLab I am trying to reduce the T feedback network(R2 R3 R4) into a Thevenin equivalent circuit looking into the network from the v- ...
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1answer
49 views

Difference Amplifier Design

I have two signal voltages V1 ranging from 100mv to 600mV and V2 ranging from 100mv to 600mv. I want to implement a difference amplifier using this opamp 601 which is a single supply CMOS. My Vdd ...
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1answer
37 views

Positive to negative rail if Opamp has Single Supply

Can the output go to -5V to 5V if an opamp has a rail supply voltage VDD = 5V and VSS = 0V
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1answer
52 views

My attempt at designing a ripple regulator - will this work?

I am recently getting into electronics design and learning about all this fascinating stuff. I wanted to challenge myself to build a ripple regulator that can take the output from a series of solar ...
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3answers
101 views

Avoiding switching transient in IC switch

I am switching an op amp input between two sources, one is ground, the other is a piezo material. I have an issue with switching transients which cause the op amp to saturate since I have a pretty ...
4
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2answers
222 views

Inverting buffer with op-amps

I know that it's easy to make a unity gain buffer with an op-amp (as a voltage follower): simulate this circuit – Schematic created using CircuitLab I also know that it's easy to make an ...
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0answers
25 views

Current in op-amp rails [duplicate]

How can I estimate the current that an op-amp will sink/source from its power supplies? Will the current in the two rails be similar, or does their relationship depend on the output level? In ...
0
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1answer
46 views

Transfer Function Of Multiple Feedback Filter - with a difference!

I posted a question yesterday about a circuit i thought was a low pass filter, however it turns out to be a transimpedance amplifier and a 2nd order low pass filter all in one! The input signal is a ...
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2answers
71 views

Differential amplifier advantage in IC manufacturing

Differential amplifier will overcome need of blocking, coupling, and bypass capacitor present in normal amplifier made from single transistor. Hence, all IC contains majorly this differential ...
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2answers
142 views

Should I assume my LMV324 is counterfeit?

I just got a bunch of LMV324IDR rail to rail op amps from ebay. I hooked one up and it seems to saturate 1.3v below the supply voltage (at 3.7v for 5v supply). There is no load at the output of the op ...
0
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2answers
76 views

differential amplifier will cancel DC present at input

In differential amplifier, it is written that "only AC signal will be amplified and DC part at the input will be canceled and hence there is no need of DC blocking capacitor". I am not getting this ...
0
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0answers
55 views

Op Amp Low Pass Filter - Feedback not connected as expected?

I have come across a circuit which I think is an active low pass filter, but it seems to have a few differences from the standard circuit I am used to seeing. Referring to the schematic, I am not ...
5
votes
3answers
330 views

How can an op-amp act as a precision diode?

I read in an article on application of op-amp that it can act as a precision diode. Precision diode is an ideal diode having very much less forward voltage drop. I am not able to understand this ...
0
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4answers
109 views

Op-Amp based power supply, what powers the Op-Amps?

I have seen some schematics of power supplies. They contain Op-Amps inside to implement negative feedback. I was wondering, hmmmm what powers the Op-Amps so they can actually work and implement ...
0
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1answer
82 views

Op amp based DC-DC voltage doubler

I have a LM471 op-amp and a single DC 5V source. Is it possible to double the source voltage using this op-amp? Can the op-amp be powered by the very singnal to be ...
1
vote
1answer
80 views

Why does non-inverting input of non-inverting amplifier need a path for DC to ground [duplicate]

Wikipedia says that, but doesn't give any explanations. The non-inverting input of the operational amplifier needs a path for DC to ground; if the signal source does not supply a DC path, or if ...
0
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5answers
70 views

Convert Single OPAMP PID to Software implementation

I have a number of analog PID implementations that I need to convert to software. In an typical example (given below), the summing junction is used to get setpoint-measured error. In decoding the P ...
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1answer
54 views

Comparators as op-amp integrator

So I figured I need an audio range function generator and was thinking of generating a square wave with a 555 and then using op-amps to integrate it into a triangle and sine. Since I happen to have ...
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3answers
96 views

when triangular input is given to differentiator how will you get square wave output [closed]

I searched so many sites they are explaining with the help of pure maths so some one help me what actually happens conceptually.
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5answers
396 views

Why does a sallen-key low pass filter not work with virtual ground?

I've been reading an article discussing single-supply op-amp design. Regarding Sallen-Key low-pass filter circuits, the author states that: A few filter topologies, such as the Sallen-Key low ...