New! Symbulator 9 for Python and SymPy
Solve circuits with the letters still in them.
Give Symbulator symbols instead of numbers and it hands back algebra — every node voltage, every element current, every power, in terms of whatever you left unknown. Describe the circuit an element at a time and ask it what you want to know.
Start here
Run it in a browser tab, or put it on your own machine.
Symbulator 9 is the current version, built on Python and SymPy. Every route below runs the same program.
Use it
-
Nothing to install
Run Symbulator online
Opens in a browser tab and runs straight away, on anything with a screen. The quickest way to try Symbulator, and enough for most coursework.
symbulator.pythonanywhere.com
Or install it, and work offline
-
Including phones and tablets
Install from the browser
A web page that installs Symbulator 9 onto your device for you. It is the installer, not the program — once it has done its job, Symbulator runs on your device and needs no connection.
install.symbulator.com
-
Unpack it yourself
Download the zip
The same program as a plain archive, to put where you want it. Use this if you would rather see what you are installing, or install it somewhere the browser cannot reach.
symbulator.com/9/local.zip
Learn it
-
Fourteen lessons, with worked problems
Read the documentation
From describing your first circuit to transient analysis, three-phase and two-ports — every lesson worked through against real textbook problems.
learn.symbulator.com
What it does
Four analyses, every element you meet in Circuits I and II.
- Analyses
- DC and AC as phasor analysis, transient in the time domain, and the complex frequency domain. Numerical circuits and, more to the point, symbolic ones.
- Answers
- Voltages at every node; current, voltage drop and power in every element. Real and complex power in AC, and the impedance each source sees looking back into the circuit.
- Equivalents
- Thévenin and Norton equivalents between any two nodes, and two-port parameters in six varieties.
- Elements
- Resistors, inductors, capacitors, mutual inductance, independent and dependent sources of both kinds, ideal operational amplifiers and ideal transformers.
- Plots
- Time-domain plots, and Bode gain and phase against frequency on a logarithmic axis.
- Expert mode
- Hand it the extra equations a problem gives you — a known current, a resistance the source sees — and it will solve for the component values you don't have.
What it will not do
Symbulator simulates linear circuits, so there are no diodes and no transistors. It also will not help with problems that turn on applying a formula selectively rather than solving the circuit through.
And it is not a replacement for your brain. You have to understand circuit theory to use it.
On a calculator
Symbulator still runs on the calculators it grew up on.
-
7
TI-89 Titanium Stable
Also the Voyage 200 and the classic TI-89. Transfer
s7.tigto the calculator; Laplace transforms come from Lars Frederiksen's DiffEq alongside it. -
8
TI-Nspire CX II CAS Beta
Transfer
s.tnsand refresh the libraries. Still in beta, so expect the occasional bug.
For developers
The engine underneath, if you want to build on it.
Not needed to use Symbulator — this is for people who want to call it from their own code, or fork it.
-
The Python package
pip install symbulator— the core of Symbulator: the description parser, the stamping engine and the solver. It is what powers the app, exposed as a library you can import and call directly. -
The source, on GitHub
Both halves are there — the solver that does the algebra, and the interface that wraps it. Symbulator is now open source under the MIT licence, so ports and derivatives are welcome under the same licence, with attribution.