How to use Circuitsteps

Updated October 8, 2026

Circuitsteps has two halves: the canvas on the right, where you draw the circuit, and the side panel on the left, where you choose what to find and read the steps. This guide covers both, from your first part to the full solution.

The editor above is the real one, with a small circuit to practise on. Try moving a part, double-clicking a resistor to change its value, or pressing R with a part selected to turn it.

Quick start

1. Choose a part from the toolbar above the canvas, or press its key, such as R for a resistor.
2. Drag on the grid from where the part starts to where it ends. Parts always snap to the grid.
3. Connect the parts by making their ends meet, using wires (W) where you need them.
4. Change the values: double-click a part, type its value (such as 4.7k) and press Enter.
5. Place a reference node (G) if you want node voltages. They are measured from it.
6. Answer the questions in the side panel: what to find, where, and with nodal or mesh analysis. Then press Solve.

Placing parts

Each part has a button in the toolbar and a key. The keys are the same as in Falstad's circuit simulator wherever it has the same part, so if you already use it, they will feel familiar.

A part stays selected in the toolbar, so you can place several in a row. Press Space or Esc to go back to the select tool.

Which way round you draw a part matters for sources. A voltage source's + is at the end you start dragging from, and a current source's arrow points back to that end, which is the way its current flows. For resistors, capacitors and inductors it only sets which way the steps measure their voltage and current.

Connecting parts

Two parts are connected when their ends are on the same point. An end can also land anywhere along a wire, not just at its ends: the wire is split there, making a junction. A wire drawn straight across another part's end connects to it the same way.

Wires that just cross each other, with no end where they cross, are not connected, as in any circuit diagram.

The canvas marks the ends of parts so you can check the connections at a glance:

• A dot is a junction, where three or more parts meet.
• A hollow circle is an end that isn't connected to anything yet.
• A red ring is an end on the middle of a part (not a wire). It doesn't connect there, so move it to the part's end.

Moving, rotating and deleting

• Select a part by clicking it. Hold Shift and click to select more, or drag a box around them on an empty part of the canvas. Ctrl A selects everything.
• Move parts by dragging them, or with the arrow keys.
• Stretch a part by dragging one of its ends.
• Rotate the selected parts a quarter turn with R. Shift R also turns the part under the mouse when nothing is selected. (With nothing selected, R picks the resistor, as in Falstad.)
• Delete the selected parts, or the part under the mouse, with Delete or Backspace. The delete tool in the toolbar deletes whatever you click.
• Undo with Ctrl Z and redo with Ctrl Y (on a Mac, Cmd Z and Cmd Shift Z). The buttons in the bottom right corner of the canvas do the same.
• Copy, cut and paste with Ctrl C, Ctrl X and Ctrl V, or duplicate the selection with Ctrl D.

Changing values

Double-click a part to change its value. The old value is selected, so just type the new one. You can use the usual prefixes, with or without the unit:

A dependent source's value is its gain, and you also choose what it depends on: the voltage across, or the current through, another part. See nodal analysis with dependent sources for worked examples.

Reading the canvas

As you draw, the canvas labels the circuit the same way the steps write it, so you can follow the solution on the diagram.

• Nodes. Everything that is connected by wires is one node, and has one voltage. Each node is shaded in its own colour, and labelled once with its voltage in a tag of the same colour, such as $V_1$. Hover over a wire or a junction to highlight its whole node. The reference node is grey, and is $V_0 = 0$.
• Currents (red). The arrow on each part is the direction its current $I_{R1}$ is measured in. A negative answer means the current really flows the other way.
• Voltages (green). The + and − beside a part show how its voltage $V_{R1}$ is measured. A voltage source shows its own polarity, and a current source has an arrow instead, as it has a direction rather than a polarity.
• Mesh currents (blue). Each loop with nothing inside it is a mesh, with a clockwise mesh current $I_1$, $I_2$ and so on.

The key in the bottom left corner of the canvas sums this up, and can be folded away.

Zooming and moving around

The canvas fits itself to the window: when there isn't room for the whole circuit, it zooms out rather than cutting it off. You can also zoom yourself with + and -, Ctrl and the scroll wheel, or by pinching a trackpad. 0 goes back to 100%, and the fit button shows the whole circuit. Scroll, or drag with the right mouse button, to move around.

Solving the circuit

Once there is a part on the canvas, the side panel asks four questions:

1. What do you want to find? Node voltages, branch currents, mesh currents or the voltage across each component.
2. Which ones? All of them, or just one node, part or mesh.
3. Which method? Nodal analysis or mesh analysis. Either can find any value.
4. How should the steps be written? For example, how the matrix is solved, and which way the currents in each equation point.

Press Solve to see the steps. Each step can be opened to show its working. From there:

• Change question goes back to the questions, with your answers kept.
• Changing the circuit also goes back to the questions, ready to solve it again.
• Solve a new circuit clears the canvas and the questions. If you didn't mean to, press Undo.

Your solved circuits

Every circuit you solve is kept in your browser, with the question you asked. Press History at the top of the side panel to see them, and click one to open it again. The most recent ones are also on the welcome page. They are only kept on the computer and browser you used, and you can remove them from the history at any time.

Every keyboard shortcut

Press ? in the editor to see these at any time. On a Mac, use Cmd in place of Ctrl.

Frequently asked questions

Why isn't my part connected?

Parts connect where their ends meet, or where an end lands on a wire. An end shown as a hollow circle isn't connected to anything, and an end shown with a red ring is on the middle of a part (not a wire), which doesn't connect. Drag the end onto the other part's end, or onto a wire.

How do I rotate a part?

Select it and press R, or press Shift+R with the mouse over it. You can also use the rotate button in the bottom right corner of the canvas.

Can I undo a mistake?

Yes. Press Ctrl+Z (Cmd+Z on a Mac) to undo, and Ctrl+Y (Cmd+Shift+Z on a Mac) to redo. Clearing the canvas with New can be undone too.

Are the keyboard shortcuts the same as Falstad's circuit simulator?

Yes, wherever Falstad has the same part or command: W wire, R resistor, C capacitor, Shift+L inductor, V voltage source, G ground, Space to select, Delete, and Ctrl+Z and Ctrl+Y. Falstad has no keys for a current source or dependent sources, so they use I, Shift+V and Shift+I.

Where are the circuits I solved?

Press History at the top of the side panel. Every circuit you solve is kept in your browser on that computer, with the question you asked, so you can open it again.