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37 views

OPAMP undervoltage detection - Trouble in real life

I've been trying to realize an OPAMP undervoltage protection circuit (see attachment, OPAMP voltage comparator topology). I'm using the AD8032 2.7 V Rail-To-Rail Amplifier for this task. In LTSPICE ...
0
votes
2answers
51 views

Active band pass filter + offset

I'm trying to know the fr equation for the following op amp configuration: I have some capacitors values for specific fr frequencies: fr = 34Hz -> C = 33nF fr = 50Hz -> C = 22nF fr = 160Hz -> C = ...
0
votes
2answers
30 views

How to calculate an op-amp's current usage based on datasheet's supply current and its Vout terminal?

This might be a dumb question so if yes, I apologize. I would like to power an op-amp off of a boost converter and I need to know how much current an op-amp would use. I'm using TI's web bench and ...
1
vote
1answer
37 views

Understanding current sourcing and sinking in TL2426 rail splitter

I have a 40dB active bandpass filter being powered off a single rail power supply with the TL2426 providing a virtual ground so I can get a dual power supply configuration. Currently, I'm having ...
1
vote
1answer
35 views

Analysing AC-Coupling differential opamp configuration

I built an audio DSP board based on CS4272 and used its reference design for the output section. The signal is getting extremely distorted when summed signal exceeds ~0.7Vpp. (Rail voltages 0V-5V and ...
2
votes
2answers
109 views

Full wave rectification by opamp

I am trying to read a current waveform from a shunt resistor series with the power line. Using a full bridge rectifier, I got the following waveform: The waveform was sampled every 2 millisecond ...
0
votes
3answers
71 views

Flat line on output of single supply sawtooth generator

I have built the following sawtooth generator using LM358 opamps: In simulation everything works fine, however in reality I get only flat line on output. Anyone got any idea what's going on?
0
votes
1answer
71 views

Reference voltage changes when connected to inverting input of op amp comparator

The capacitor C2 keeps the value of a slow varying signal for some time. The capacitor discharges through the two resistors R3 and R4 with a time constant of \$\tau = RC = 10\mu F \times 1M\Omega = ...
4
votes
2answers
1k views

Single supply non-inverting amplifier using op amp

I'm working on building a distortion guitar effect pedal for an analog electronics class I'm taking. I am struggling with building an amplifying circuit using an op amp (we just began learning about ...
0
votes
0answers
43 views

Remove Echo in an Op Amp

I have been working with a distortion circuit that has an op amp amplifying the volume before sending it through the diodes. The op amp is configured as a non-inverting op amp with a feedback resistor ...
0
votes
2answers
79 views

Why do we use one bias (VCC) for transistor amplifier circuits and 2 supplies for opamp circuits? [closed]

Opamps are said to have 2 supplies, so that the output can rail between these two points, then why do transistors have only one bias point.
6
votes
3answers
688 views

Current sense amplifier + op-amp buffer + ADC: Measuring down to 0 with a single supply

I'm thinking about current sensing with a high dynamic range (10 mA - 20 A) and using LTC6102 as a high-side current sense amp (the voltage would be 54.6 V max, a 13S6P Li-ion battery). ...
4
votes
3answers
1k views

Strange opamp's output impedance in spice

I'm simulating this circuit in Micro-Cap, which is the clipping stage of a guitar effect. The opamp model is the "NE-5532" I want to measure the input and the output impedance. I expected an output ...
5
votes
1answer
244 views

What might be causing an op amp to fail in a voltage follower circuit?

I have the following super simple op amp circuit that makes use of the AZV321 single op amp (https://www.diodes.com/assets/Datasheets/AZV321.pdf) in order to balance the voltage on a pair of ...
2
votes
2answers
329 views

Bandpass Filter: Single supply op amp design

I have taken on a hobby project and I am trying to make a circuit which would be able to identify an acoustic signal with a frequency of 40kHz. Here is the circuit of a band pass filter for this: ...
0
votes
1answer
94 views

Running +/- 15V opamp at 3.3v

I find I need a comparator, because I have a problem with an optical sensor triggering multiple interrupts, like this question: https://arduino.stackexchange.com/questions/13287/interrupt-fires-...
0
votes
1answer
120 views

Single supply opamp colpitts oscillator

I'm designing a Colpitts oscillator with a single supply rail-to-rail opamp powered with 3.3 V. The positive input of the opamp is set to VDD/2 to offset the negative part of the oscillations so ...
1
vote
4answers
141 views

Differential amplifier with common voltage far above the rail?

I have a thermocouple with one end connected to +24V. I want to be able to read the voltage (-5mV - +20mV) on it using a 3.3V ADC. The most reasonable solution I see is lowering the voltages using ...
3
votes
1answer
150 views

Single supply op amp with input attenuator

I'm designing a guitar headphone amplifier that uses a single supply op-amp as the output stage to the headphones. I'm using a potentiometer after the final JFET stage and before the op-amps as a ...
1
vote
2answers
104 views

Difference between these two op amp circuits

I came across this circuit for a non inverting op amp which is biased Vs/2. I'm wondering what the difference bettween these two circuits are? What is the purpose of R3 in the first circuit and how is ...
2
votes
1answer
243 views

Can a Single Supply Powered Op-Amp Handle Negative Input Voltage?

I have an input sine wave at 300mV peak to peak. I want to filter this sine wave to eliminate noise and distortion. I am planning to use the LMx58-N op-amp family, powered using a single supply: 3V ...
1
vote
0answers
74 views

Can this circuit be simplified?

The circuit is a LPF with a buffer stage in front of it that uses a linear pot. to control gain & attenuation. The setup is such that the response of the linear pot. is similar to a log. pot.. A ...
-1
votes
1answer
545 views

Current source with op amp and transistor

I'm building current source with OP AMP LM358 and MOSFET transistor IRF5305. Here's schematic diagram of the circuit: I have two questions about it: 1) Maximal gate-source voltage of IRF5305 is +/-...
0
votes
1answer
116 views

Op amp AC simple supple (Buffer) LM324N

I´m working on a proyect and i use OrCad/Spice to simulate the op amp that i gone use and my Voltage(output) signal is Constant and my Voltage(Input) is sinusoidal.
0
votes
3answers
150 views

Single Suppy Opamp for inverting amplifier produce negative voltage signal

i made an inverting amplifier circuit using CA3130, the supply just the positive voltage and GND for V- supply. the circuit is used for full wave rectifier because the signal is around 1 MHz and 500 ...
0
votes
1answer
51 views

transimpedance op-amp wrong and random output

from my previous question (this link) i advised to using operational amplifiers to converting current changes to voltage changes then i followed the standard circuit for a transimpedance ...
-3
votes
2answers
89 views

set gain on inverting preamp

I built (more or less) this opamp. I know normally the gain would be defined by the ratio of the feedback resistor to the input resistor but here there is no feedback resistor so how do I tweak the ...
0
votes
2answers
717 views

Why is the MCP601 better suited than the LM833 for single supply applications?

Still not answered, please need some help. If you guys don't know the answer don't be afraid to admit it, but I want to generate discussion around potential solutions/calculations and not semantics ...
1
vote
1answer
296 views

Problems while using op-amp as a comparator on a single supply

Here's my circuit: . Application: The circuit is for ground fault detection. When a fault current of 20mA flows through the primary of the current transformer (1:660), it generates a current of ~30uA ...
0
votes
2answers
160 views

How to get inverting amp in an electronics project with 1 battery

I am trying to invert the signal from a microphone for a simple noise cancellation project. I am using a 3.7V lipo battery, right now I am trying to use a single supply op amp (TLV2462), but don't ...
0
votes
2answers
375 views

Why does this single supply non inverting Op-Amp saturate?

I have this simple non inverting setup made with a TL082IP Op-Amp and a gain set to 2 (R1 = R2). Since I will only have positive voltage 0V to 5V to amplify, I use for simplicity a single 12V/0V ...
4
votes
2answers
734 views

Saturation problem of comparator [duplicate]

I am trying to design a comparator using a 741 IC, with a single supply of 12V. I have set the reference to 2V and I require the output to toggle between 12V to 0V. but the problem I am facing is the ...
0
votes
3answers
115 views

OPAMP - Current sense - unexpected behavior

I want to trigger an interrupt on an ATMEGA328P, when the current of a load is below a certain value. Therefore I designed the following differential amp circuit using an LM358 Below picture shows ...
0
votes
1answer
436 views

How to calculate frequency of this Op Amp square wave oscillator?

I was trying to come up with the equation to calculate the frequency of this circuit. R1 and R2 are creating analog ground because I am using bipolar op amp for a single supply operation. Thank you ...
0
votes
1answer
553 views

NTE941M Non-inverting OpAmp Has Non-zero Output with 0V Input

I have a non-inverting, single-supply, variable gain op-amp circuit configured in accordance with this diagram: Vcc: +16V Rf: 800k Ohm Potentiometer R2: 100k Ohm I have the potentiometer set to ~...
0
votes
1answer
398 views

Limited output voltage swing in lm358 opamp

I was having trouble designing a small headphone amplifier that used lm358 as input stage. After verifying the push-pull output stage was correct and that every DC point was correct too (output ...
0
votes
2answers
325 views

Supply Voltages for Inverting Amplifier

I want to use an inverting amplifier to linearly shift and convert a signal with voltage range -10...+10V into 0 ... 3.3V for an ADC of a microcontroller. I wanted to use the circuit presented in this ...
1
vote
6answers
2k views

Single supply amplifier for driving 8ohm, 0.7W speaker

I am trying to build a simple amplifier to drive an 8ohm, 0.7W speaker using a 5V single supply. Audio fidelity is of little importance, since it is a cheap speaker, but I would like the output to be ...
0
votes
1answer
137 views

How to make LT1168 instrumentation amplifier work with single supply?

I am using the LT1168 instrumentation amplifier for my project and I am trying to figure out how to make it work with a Li-Poly 3.7 Volts battery. I am not able to understand the single supply ...
-1
votes
2answers
297 views

offset errors in opamp in DC and AC [closed]

I want ask about When the offset errors be more serious, when amplifying dc or ac signal in op-amp i search but noting found in this area
3
votes
2answers
468 views

Opamp output current

In experimenting with a follower circuit using an NE5532 opamp, I am trying to determine the maximum allowable output current for design purposes. The datasheet is lacking curves in this area, but ...
0
votes
0answers
56 views

Two Op Amp In-Amp Voltage output

I mounted the following circuit using a LM324, where Val = 5v, Vref = 1.78v, R6=18K and R7=10K. I measured Vu and i'm getting a very close value to Vref, why? Edit: V- and V+ are connected to Vref ...
2
votes
2answers
192 views

Single supply OPA445?

So basically I'm trying to make a circuit for a piezo-electric actuator. I only have access to a single supply at +70V for my op amp, an OPA445AP. Vin varies between 0 and +3V. I've looked at the help ...
2
votes
2answers
467 views

Why must this capacitor be a “low leakage” type?

I was reading this article discussing non-inverting opamps and when presenting the above single-rail opamp circuit it gave the following not regarding capacitor C2: Capacitor C2 type: It is ...
2
votes
1answer
181 views

pH sensor buffering, gain, and offset with one inverting opamp

I'm working on the above mentioned circuit. I'm a hobbyist with little electronics training so don't laugh if something terribly dumb comes out of my keyboard please. Anyway, a different question on ...
4
votes
2answers
716 views

Simple single-supply op amp virtual ground questions

I found this circuit online and made it and it works. It uses an LM358 op amp to amplify an oscillation from a 555 in astable mode. simulate this circuit – Schematic created using CircuitLab ...
0
votes
2answers
334 views

Opamp voltage supply

Given an opamp to which we can apply a supply voltage of 5v. Does this mean it has to be only +2.5 and -2.5 V or could it be 0 and +5v. Is there a difference? Thus is it possible to convert any opamp ...
1
vote
0answers
443 views

Output to ground rail on single-supply op-amp with grounded load

I'm having some problem comprehending the internal functions of op-amps and I'd appreciate any insight in to why my circuit behaves the following way: I'm working with TI's OPA548 op-amp (PDF ...
0
votes
1answer
312 views

Anything wrong with this level shift and amplify op amp circuit?

I posted this circuit in a question about protection clamping, but got a lot of questions around the circuit itself. Is this not a good / the normal way to shift and amplify a low amplitude (75mv) ...
0
votes
1answer
202 views

Op-amp for pulse width modulation, 5v single rail supply [closed]

For experimental - hobbiest purpose, I'm trying to control one 3-color led with the following circuit: Power: single rail, 5v. Signal generator: triangular 0-5v, 500 Hz (in next step, signal ...