Questions tagged [circuitlab]

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

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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/...
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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 ...
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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 ...
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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 ...
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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 ...
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Plot Z vs Freq for RL-C circuit

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 a AC ...
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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 ...
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2 votes
1 answer
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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, ...
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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?...
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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 ...
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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. ...
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2 votes
1 answer
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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 ...
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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+...
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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 ...
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1 vote
1 answer
472 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 ...
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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. ...
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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 ...
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1 vote
2 answers
6k 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 \...
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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 ...
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1 vote
0 answers
174 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 ...
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2 answers
292 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, ...
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