https://brandonli.net/semisim/

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Brandon's Semiconductor Simulator

Draw your own circuits. Turn on voltage and see what happens. Some
features of my program include:

  * Interactive circuit drawing
  * Visualization of electromagnetic fields
  * Many materials (metals, semiconductors, dielectrics, and more)

Simulator Run Simulator

You need a good computer to run this simulation on your browser.
There is also a downloadable version that's much faster (but requires
Java).

Want to know more? You can read about it here.

(c) Brandon Li, 2025. Ported to Javascript with the help of Paul
Falstad.

If you have any suggestions or examples you'd like me to add, please
contact me at [email protected].

Simulation Examples

Simple Circuits

Basic circuit Circuit
Resistor Resistor
RC Circuit RC Circuit
Electric Dipole Electric Dipole
Ohm's Law Ohm's Law
LC Circuit LC Circuit
Maze Maze
Galvani Potential Galvani Potential
Bridge Rectifier Bridge Rectifier
Electrostatic Shielding Electrostatic Shielding

Semiconductor Devices

PN Junction Diode PN Junction Diode
NPN BJT BJT (NPN)
PNP BJT BJT (PNP)
N-MOSFET Enhancement N-MOSFET (Enh.) - new
N-MOSFET Depletion N-MOSFET (Dep.) - new
N-JFET N-JFET
Schottky Diode Schottky Diode
Thermoelectric cooler Thermoelectric Cooler
LED Light-Emitting Diode

Digital Logic

Ring Oscillator Ring Oscillator (very slow)
DRAM Cell DRAM Cell

Updates

5/10/2022:

  * Tweaked default dielectric/ferromagnet parameters
  * Made N-MOSFET examples more accurate
  * Improved Schottky diode demo