Free · no account · no install
Online electric
circuit simulator
A free electric circuit simulator in the browser: build a circuit on a breadboard, measure voltage and current, and see its schematic drawn live.
Power supplyset to 9 V
Resistor220 Ω
Ammeterreads the current
01
Try Ohm's law right now
Change the voltage or the resistance, and watch the current.
Mini-lab · Ohm's law
Voltage U
Resistance R
The same circuit in the lab, with the 9 V and 220 Ω example.
02
What you can measure
Four measuring instruments, with range selection and digital or needle display.
| Meter | What it measures | How to connect it | Unit |
|---|---|---|---|
| Voltmeter | The voltage across a component | In parallel | V |
| Ammeter | The current through a branch | In series | A |
| Ohmmeter | The resistance of a component | Circuit off | Ω |
| Wattmeter | The power used by a component | Current in series, voltage in parallel | W |
Highlighted: the meters of the mini-lab. A wrongly connected meter, a short circuit or an exceeded range is flagged.
And the components you can build
Adjustable power supplySet the voltage
CellsOne or more
ResistorsE12 or any value, colour bands
LampsGlow with their power, burn out if overloaded
MotorTurns when current flows
PotentiometerVariable resistance
SwitchesOpen or close the circuit
Conductor wiresLength, cross-section, material
03
How it works
Four steps, as in a real lab.
1Choose
A source, resistors, a lamp from the palette.
2Build
Place them on the breadboard, join them with red and black cables or link chips.
3Close the loop
Solved in real time with Ohm's and Kirchhoff's laws.
4Measure
Compare the reading with the lesson's calculation.
Example9 V and 220 Ω → I = 9 / 220 ≈ 40.9 mA
Frequently asked questions
Is the circuit simulator free?
Yes. It runs in the browser, with no installation and no account.
Which devices does it work on?
On a computer and on a tablet, in a recent browser.
How is the circuit calculated?
With Ohm's law and Kirchhoff's laws (nodal analysis), in real time, as soon as the loop is closed. The schematic view with IEC 60617 standard symbols is redrawn at every change: you see the real circuit and its diagram side by side.
What else does it calculate?
With a simulated clock, the quantity of electricity Q = I·t and the energy W = P·t. It also shows current arrows.
Can I break something?
No, it is risk-free: you can burn out a lamp, short a cell or exceed a range just to see what happens, then start again.
Is it electronic design software?
No. Elec Class is not electronic design software: it is made for learning, to understand what happens in a simple circuit and practise. Each topic has its lesson sheet and practice problems with answers.
Who is it for?
Technical and vocational secondary students, preparatory year students, electrician trainees, and teachers who project an experiment in class.
Can I use it in class?
Yes, freely: projected on the board or on the students' computers, with practice problems to set. See Using Elec Class in class.
04
Practise
Your own circuit, or a guided start.