Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [circuitlab]

CircuitLab is a browser-based schematic and circuit simulation application.

25 questions
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Why does the 2N7000 in CircuitLab not behave the same as on my breadboard?

When simulating the 2N7000 in CircuitLab, I was surprised to see that the current was lower than expected for my circuit (90mA at the drain) when the gate is at 3.3 V. So, I built a quick breadboard version and saw that the current was actually…
Nick Bolton
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Single-supply op-amp behavior with 0V input

I am confused by how op-amps work. I have a single-supply op-amp: the power rails are +5V and ground. The circuit in the image says the op-amp is an LM741 but it's actually the op-amp built into the Cypress PSoC 4200M chip (data sheet). My…
Willis Blackburn
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CircuitLab voltage source question

I was having a problem with one of my circuits in CircuitLab, and traced it down to my sources always enabled, even if I switch them off by connecting to an open switch. This seems to be so simple, but I can't figure out it. Here is a simplified…
tcrosley
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Is there a minimum voltage for digital logic (eg XOR) in CircuitLab?

I am trying to design an edge to glitch converter (XOR time delay) that works at 3 V. For context: This is to wake an ESP8266 when a sensor value changes. I am fairly certain at this point that the ESP8266 can't interrupt for deep sleep wake on…
Nick Bolton
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1 answer

CircuitLab DC parameter sweep problem circuit

The following circuit, taken from this answer seems to give odd results when doing a parameter sweep simulation on CircuitLab. Is the problem with CircuitLab, or is there some problem with the circuit that I do not see. simulate this circuit –…
Math Keeps Me Busy
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Simulation Error in Circuit Lab with 2 Dependent Sources

simulate this circuit – Schematic created using CircuitLab I'm practicing some problems and came across this circuit. It asks for the Thevenin equivalent with respect to terminals A and B. I solved it by hand and have the correct answer and also…
elimenohpee
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BJT Differential Amplifier problem

I have tried to reproduce and understand the BJT differential amplifier, and unfourtunetely I have encountered some issues. The circuit is from Art of Electronics, 3rd edition. First, my question is on what basis does the circuit function? I would…
David Ab
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Why is CircuitLab so slow to simulate this simple circuit? (Op Amp DC-coupled to BJT phase splitter.)

Not sure how much is known or published about the back end of CircuitLab, but: While simulating a different circuit, I noticed very long simulation time. I narrowed the culprit down to the below portion. With a DC sweep on V1 from 0V to 5V and a…
Theodore
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Difficulty using CircuitLab to build a Zener Diode Voltage Regulator Circuit

So I'm trying to build a Zener Diode Voltage Regulator in CircuitLab. I've been searching around Google for some insight into building these, however, I'm required to use a triangle wave input, while the examples I've been seeing online do not.…
Athena Moraitis
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How to achive mutual inductance and CM choke simulation in CircuitLab?

This site is using CircuitLab. In some SPICE programs it is possible to simulate CM choke. For example: Mutual Inductance is designated in a SPICE netlist by beginning the first word (label) of a new line with the letter "K". It is unique …
pnatk
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Modeling impedance matching network

Background I'm looking at the RF (LNA_IN) pin of ESP32 as described in esp32_hardware_design_guidelines. According to this document, the output impedance of the RF pins of ESP32 are (30+j10) or (35+j10) Ω (depends on package), while the antenna…
Amir Gonnen
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How to simulate series capacitors in CircuitLab?

I am reading through the book Practical Electronics for Inventors, specifically the section on capacitors. I read that capacitors in series will an have equivalent capacitance C with formula $$ C=(1/C_1 + 1/C_2 + ... + 1/C_n)^{-1} $$ If we connect…
nwsteg
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Circuitlab - How can I create my own transistor model?

I would like to create some transistors, like the S8050 transistor, for to use in CircuitLab. What I found is https://www.circuitlab.com/docs/custom-device-models/ If I open another existing transistor, then I see variable namings that give me no…
iPadawan
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Plot Z vs frequency for RLC circuit in CircuitLab

I am trying to simulate the resonance frequency of an antenna that can be modeled by a resistor in series with an inductor, both in parallel with a capacitor: By attaching the antenna to an AC current source and doing a frequench sweep, I want…
Leo
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CircuitLab with fixed frequency

Inspired by this SE question, I was wondering how good CircuitLab would be a solving this type of problem. Why do we not include the current source when finding the Thévenin equivalent impedance? simulate this circuit – Schematic created using…
Mattman944
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