Is embedding the circuit simulator free?

Yes. It is free to embed on any site, with no account, no API key and no usage limits. The whole simulation runs in your visitor’s own browser, so there is no server cost — we only ask that you keep the small "Circuit Simulator by LK Forge" credit line that comes with the embed code.

What can visitors do with the embedded simulator?

They set a battery voltage and three resistor values, and switch the resistors between series and parallel. The tool draws the circuit with current flowing along the wires — faster where the current is larger — and a live panel shows the total resistance, the total current, the power, and the voltage drop or branch current at each resistor, all from Ohm's law V = I·R.

Does the embed teach Ohm's law and series vs parallel?

Yes. Every value is computed directly from V = I·R: in series the resistances add and the current is shared, in parallel the reciprocals add and the voltage is shared. Flipping the toggle with the same three resistors shows how the total resistance, current and power all change — the core of a series-and-parallel-circuits lesson.

What iframe height should I use, especially on mobile?

The snippet ships with height="880", which is tall enough that the circuit diagram, the series/parallel toggle, the four sliders and the readouts all fit without clipping even on a narrow phone where everything stacks into a single column. On a wider page the widget simply centres within its max-width of 560px. If you want it shorter you can lower the height, but 880 is the safe default across screen sizes.

Where can I embed it — WordPress, Wix, Squarespace, Notion?

Anywhere you can add HTML, because it is a standard iframe. In WordPress use a Custom HTML block; in Squarespace a Code/Embed block; in Wix an Embed HTML element; in Ghost an HTML card; in Notion paste the /embed/circuit-simulator/ URL as an embed. On a plain HTML page or an intranet, paste the snippet straight into the markup.

Does the embedded simulator track visitors or set cookies?

No. Everything runs locally in the visitor’s browser — nothing is uploaded. The embed sets no tracking cookies and sends no analytics, so it is safe to place on a privacy-sensitive site, an intranet, or a page for students.

Widgets

How to Add a Circuit Simulator to Your Website

LK Forge · 4 min read · Updated September 2026

You can add a full DC circuit simulator to any website, blog, or classroom page with a single line of code — free, with no sign-up, no plugin, and no script to install. Visitors wire resistors in series or parallel and watch Ohm's law solve the circuit. This guide covers the fastest way to embed the Circuit Simulator, what it teaches, and where it works.

The quickest way: paste one embed snippet

An embed is just an <iframe> that loads the simulator from lkforge.com, plus a small credit line. Copy this into your page’s HTML where you want the widget to appear:

<iframe src="https://lkforge.com/embed/circuit-simulator/"
        width="100%" height="880" loading="lazy"
        style="border:0;max-width:560px"
        title="Circuit Simulator by LK Forge"></iframe>
<p><a href="https://lkforge.com/tools/physics/circuit-simulator/">Circuit Simulator</a>
   by <a href="https://lkforge.com/">LK Forge</a></p>

The <iframe> is the live simulator; the <p> underneath is a plain credit link. Keep that line — the visible link is what keeps the widget free to embed. You can also copy this exact code straight from the LK Forge widget gallery.

What the widget shows

The simulator opens with three resistors in series, so a visitor sees a working circuit immediately and can then change it:

Series / parallel toggle: rewire the same three resistors and watch everything recalculate.
Battery and three resistors: four sliders feed straight into Ohm's law.
Flowing current: dashes run along the wires, faster where the current is larger.
Live readouts: total resistance, total current, total power, and each resistor's voltage or current.

Pick the right height

The snippet uses height="880", which fits the circuit, the toggle, the sliders and the readouts without clipping even on a narrow phone, where they stack into one column. On a wider page the widget centres within its max-width:560px. That single height works across screen sizes, so there is nothing to tweak for mobile.

Where it works

Because it is a standard iframe, the embed works anywhere you can add HTML:

WordPress: add a Custom HTML block and paste the snippet.
Squarespace: use a Code / Embed block.
Wix: add an Embed HTML / iframe element.
Ghost: insert an HTML card.
Notion: paste the /embed/circuit-simulator/ URL and choose "Create embed".
Plain HTML, an intranet, or a lesson page: paste the snippet straight into the markup.

That’s the whole job. Copy the embed code from the widget gallery and paste it wherever a lesson or a blog post on Ohm's law, series and parallel circuits, or electric power needs a circuit students can actually rewire.

Grab the embed code from the LK Forge widget gallery — free, no sign-up.

Open the Circuit Simulator

Frequently asked questions

Is embedding the circuit simulator free?: Yes. It is free to embed on any site, with no account, no API key and no usage limits. The whole simulation runs in your visitor’s own browser, so there is no server cost — we only ask that you keep the small "Circuit Simulator by LK Forge" credit line that comes with the embed code.
What can visitors do with the embedded simulator?: They set a battery voltage and three resistor values, and switch the resistors between series and parallel. The tool draws the circuit with current flowing along the wires — faster where the current is larger — and a live panel shows the total resistance, the total current, the power, and the voltage drop or branch current at each resistor, all from Ohm's law V = I·R.
Does the embed teach Ohm's law and series vs parallel?: Yes. Every value is computed directly from V = I·R: in series the resistances add and the current is shared, in parallel the reciprocals add and the voltage is shared. Flipping the toggle with the same three resistors shows how the total resistance, current and power all change — the core of a series-and-parallel-circuits lesson.
What iframe height should I use, especially on mobile?: The snippet ships with height="880", which is tall enough that the circuit diagram, the series/parallel toggle, the four sliders and the readouts all fit without clipping even on a narrow phone where everything stacks into a single column. On a wider page the widget simply centres within its max-width of 560px. If you want it shorter you can lower the height, but 880 is the safe default across screen sizes.
Where can I embed it — WordPress, Wix, Squarespace, Notion?: Anywhere you can add HTML, because it is a standard iframe. In WordPress use a Custom HTML block; in Squarespace a Code/Embed block; in Wix an Embed HTML element; in Ghost an HTML card; in Notion paste the /embed/circuit-simulator/ URL as an embed. On a plain HTML page or an intranet, paste the snippet straight into the markup.
Does the embedded simulator track visitors or set cookies?: No. Everything runs locally in the visitor’s browser — nothing is uploaded. The embed sets no tracking cookies and sends no analytics, so it is safe to place on a privacy-sensitive site, an intranet, or a page for students.