Questions tagged [operational-amplifier]
Questions relating to the construction and applications of operational amplifiers, which are DC-coupled, high-gain electronic voltage amplifiers with a differential input and, usually, a single-ended output.
9,045 questions
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Low pass filter output stuck at supply voltage
The schematic shows 2 transimpedance amplifier circuits on the first stage, for reference and sample photodiodes. The outputs are then connected to sallen-key butterworth circuits for low pass ...
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How do I derive the exact frequency formula for this integrator + non-inverting Schmitt triangle/square oscillator?
I’m trying to understand (and derive) the frequency equation for the classic triangle/square function generator made from an inverting integrator driven by a non-inverting Schmitt trigger. The ...
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What to consider when picking op-amp for compensator design?
I was learning to make a buck converter on my own, and came across Type 3 compensator design. I used this application note from TI and calculated my values on MatLab. The cross-over frequency is at ...
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Opamp circuit design [closed]
Design a circuit using opamps to solve the following differential equation. The output should give y(t). x(t) is an available input sign.
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Proper way to simulate op-amp phase/gain margin with input capacitance?
I would like to simulate the phase margin of an op-amp configured as a transimpedance amplifier. I am using the ADA4817. For high speed op-amps you have to be careful about parasitic capacitance to ...
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Existing old type LM324 based automatic voltage stabilizer circuit evaluation
I wanted to build up a voltage stabilizer to study its performance.
I got 3 simple circuit diagrams below from circuitspedia.com - Stabilizer Circuit Diagram. Perhaps someone design it without ...
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Can you sum "hot" and "cold" balanced signals with op amps?
I have four home built tie clip mikes. The output of the electret is being fed to a chip (MAX9814?) to give a line level, passed to a 600:600 transformer to create a balanced signal out to the mixer ...
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THS4541 error message in LTspice
I’ve trying to use THS4541 in my circuit but am getting the following error message:
I know it relates to THS4541 but can’t figure out what’s the issue. I have created a symbol using LTSpice’s ...
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Amplifying signal post low pass filter
I’ve designed an elliptic low pass filter with a very steep roll-off around 18–20 MHz. The filter’s response is close to what I need, and the cutoff behavior is critical, so my goal is simply to shift ...
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Am I able to find Vz as if it was a voltage divider of V_out?
So I asked ChatGPT to find V_out and one of the steps it did was to define V_z as (R3 / (R3+R4)) * V_out. Though I didn't continue with this method, it left me wondering if that is correct to define ...
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Low-side current sensing with negative voltage
simulate this circuit – Schematic created using CircuitLab
I am working on a power converter circuit and need to sense the current coming out of the rectifier. A high-side current sense setup ...
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Effect of op-amp offset when \$V_{in} \approx V_{OS}\$ in a log amplifier
In the standard log amplifier (op-amp with BJT in feedback, resistor \$R_1\$ at the input), I modeled the op-amp input offset as a small DC source \$V_{OS}\$ at the non-inverting input. Assume \$V_{in}...
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Errors when building a single-supply Schmitt Trigger?
I was attempting to build a particular Schmitt Trigger in order to learn more about it. It's from the "Design with Operational Amplifiers and Analog Integrated Circuits" by Sergio Franco. On ...
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Noise in op-amps
I'm currently working on building a circuit with the objective of filtering 300 kHz signal and attenuating other harmonic orders in the signal. The design of the circuit is shown in the following ...
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Controlling motor speed using an IR sensor; how can I improve the PID controller circuit?
Is the feedback given correctly in this circuit? The motor is supposed to adjust to the changing values of IR sensor, but my motor runs at maximum RPM when the voltage at the base is greater than 0.7 ...
