Questions tagged [circuitlab]

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

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Help "Non-finite value" Circuit Lab Error

After running DC Simulation in CircuitLab, I get this error message: "Error building graph: non-finite value." What is going on? I'm new at this, so anything could be wrong. First, to ...
Effexxess's user avatar
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Common base configuration

I have tried to implement this circuit of common base configuration but the power supply used in the lab is very confusing and I suspect it’s the reason why my readings aren’t turning out right (it’s ...
Shahad's user avatar
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Is CircuitLab's coupled inductor code broken?

I was working on an answer for this question, using CircuitLab but getting inexplicable results. The circuit oscillated, but the voltages were off. I was using CircuitLab's coupled inductor feature ...
Math Keeps Me Busy's user avatar
2 votes
3 answers
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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 ...
David Ab's user avatar
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Proper way to model solar panel using CircuitLab

I'm trying to simulate a very simple (primitive?) circuit to charge a battery from a solar cell. The solar cell was scavenged from a long string of lights. With a 50 Ω resistor it produces about 6.6 ...
Bryan Hanson's user avatar
4 votes
1 answer
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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 ...
Nick Bolton's user avatar
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10 votes
3 answers
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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 ...
Nick Bolton's user avatar
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1 vote
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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/...
nwsteg's user avatar
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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 ...
iPadawan's user avatar
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3 votes
1 answer
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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 ...
Math Keeps Me Busy's user avatar
3 votes
1 answer
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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 ...
elimenohpee's user avatar
2 votes
1 answer
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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 ...
Theodore's user avatar
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1 vote
2 answers
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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 ...
Leo's user avatar
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How can I set the maximum current in my CircuitLab circuit?

I have designed a circuit for two electromagnets to be turned on and off by a Raspberry Pi, but the total current draw by the circuit is 10.99A and my power pack has a limit of 2A. How can I simulate ...
Orlando Alexander's user avatar
2 votes
1 answer
138 views

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, ...
Athena Moraitis's user avatar
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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?...
Mattman944's user avatar
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353 views

How do I do calculation in CircuitLab? How do I provide +Vcc and -Vcc to the OpAmp?

Here is my simple circuit. I would like to test whether the output is correct as per manual calculation. According to manual calculation, Gain=3.1, Vo=10.54V. My question are: How do I do that ...
AirCraft Lover's user avatar
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CircuitLab simulation of 555 timer - OUT HIGH always delivering 5V irrespective of Vcc?

I've scratched together a design for a 555 timer based driver for an IR540 MOSFET. But in CircuitLab the simulator shows the 555's OUT voltage is always 5V when high, for Vcc ranges 3.3V through 24V. ...
Craig Ringer's user avatar
3 votes
1 answer
266 views

How to achieve 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 ...
pnatk's user avatar
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3 votes
2 answers
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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+...
Amir Gonnen's user avatar
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2 answers
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Simulating the discharge of a condenser using CircuitLab

Intro: While studying for a Signals and Systems exams for tomorrow i decided to simulate an exercise and prove my answers are right. simulate this circuit – Schematic created using CircuitLab ...
WhiteGlove's user avatar
1 vote
1 answer
782 views

How can I add variable duty cycle PWM to a CircuitLab simulation within a question?

This is my first attempt to simulate a circuit in the time domain with CircuitLab. In order to ask a proper question about something similar driven with PWM, I'd like to add an adjustable duty cycle ...
uhoh's user avatar
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1 vote
1 answer
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Battery charging circuit

Can anyone assist me with correcting this circuit? I'm trying to build a 12 V lead acid battery charger that would have a green LED indicator when charging and a red LED indicator when fully charged. ...
user169847's user avatar
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2 answers
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How do I use Circuit Lab to show me Voltage and current information on this circuit?

I have a bunch of red LEDs, I don't have their data sheet and I am trying to figure out a safe resistor to use to lower the current across them safely. My current setup is as follows: simulate this ...
RenegadeAndy's user avatar
1 vote
2 answers
8k views

Voltage Clipping with Two Series-Opposing Zener Diodes

Theory Schematic for Voltage Clipping with Two Series-Opposing / Bidirectional Zener Diodes Consider the following schematic for voltage clipping with two series-opposing/bidirectional Zener Diodes \...
Discbrake's user avatar
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5 votes
4 answers
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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 ...
Willis Blackburn's user avatar
1 vote
0 answers
191 views

PhotoMOS simulation circuit

I want to simulate the following PhotoMos in CircuitLab for switching circuit but i didn't find the model for any photomos in CircuitLab. I was preparing a simulation for a switching MOSFET circuit ...
Pakito's user avatar
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5 votes
2 answers
364 views

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, ...
tcrosley's user avatar
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