Circuit Construction Kit: DC & AC Virtual Lab Community

Key ideas

• Batteries push current around a complete loop.
• In a series circuit the same current flows through every part.
• In a parallel circuit the voltage is the same across each branch.
• A short circuit has almost no resistance and a huge current.
• Metals like a paper clip or a coin conduct, but an eraser, a dollar bill and a hand hardly do.
• Real batteries have internal resistance, so their voltage sags when they supply a lot of current.
• A fuse protects a circuit by blowing when the current is too large.
• Everything the sources supply is used by the parts, so power supplied equals power used, and the current arriving at every junction equals the current leaving it (Kirchhoff).

Things to try

• Load the Series preset and add a third bulb.
• Load the Conductor test preset and try the paper clip, coin, pencil, eraser, dollar bill and hand.
• Drag the ammeter ring onto different parts and compare its reading with the current shown in the graph.
• Load the Fuse demo, then raise the fuse rating and click the fuse to replace it.
• Raise the battery's internal resistance and watch the bulb dim.
• Load the RC charge preset, close the switch and watch the capacitor voltage rise in the graph.
• Switch to Schematic and Electrons to see the textbook view and the real electron flow.

Where this is used

Electricians and engineers test circuits in simulators like this before building real hardware. Fuses and breakers keep homes safe, and batteries with internal resistance explain why phones get warm.

How to ask a question people can answer

A good thread on the Circuit Construction Kit: DC & AC Virtual Lab saves everyone time. Start with a title that names the exact problem, such as the input you used, the result you expected and the result you got. A title like “Not working” is hard to answer, while a title with the specifics gets replies quickly.

• Say what you tried. List the steps you followed and any settings you changed, so replies do not repeat what you already did.
• Share a small example. A short sample input and the output you saw is worth more than a long description. Remove anything private first.
• Mention your setup. Your device, browser and whether you are on a phone or a computer can explain many odd results.
• One question per thread. Separate topics get clearer answers and are easier to find later with the search box above.
• Come back and reply. If a suggestion worked, say so and upvote it, and if you found the fix yourself, post it for the next person.

Community rules

Be kind, stay on topic and keep personal data out of your posts. Do not post adult, hateful or illegal content, advertising or repeated links. Every post is shown with its author’s username and date, and posts that break these rules can be hidden by moderators. This space is for help with the Circuit Construction Kit: DC & AC Virtual Lab and related tasks, and it is separate from the sitewide discussion forum where broader topics live.