Skip to content
kuazaraKuazara
Log in

Science · Electric circuits

Circuit components and a simple electric circuit

What is inside a torch? Learn what the cell, bulb, switch and connecting wire each do, and find out why a bulb only lights when the circuit is an unbroken path.

  • 15 min
  • 1 simulation
  • Mini quiz

Updated:

Preview

The question

When there is a power cut, you take a torch out of the drawer, press the button and the light comes on. What is happening inside that small device? And why does the torch not light at all if you put the battery in the wrong way round or a wire comes loose? Could it be that electricity actually has to go round a loop for the light to come on?

Try it yourself

No account needed: change the values and check your answer. Some simulations ask for a prediction before they start; it doesn't matter whether it's right or wrong.

Ordering

Steps for building a simple circuit

Order the cards by dragging them or with the up and down buttons. When you have finished, submit your answer.

Prediction

Predict first

You have connected all the wires, but the switch is open. What do you think happens to the bulb?

It doesn’t matter whether you’re right; the simulation opens once you choose.

Share: Share to Google Classroom (opens in a new tab)

Embed the simulation on your site

Paste this code into the HTML of your blog or school site. Visitors try the simulation without an account; no progress is saved.

The embedded page sets no cookies and does no tracking. A small link back to Kuazara sits underneath.

Log in to continue

The rest of the lesson is waiting for you, with a mini quiz. Creating an account is free.

Start for freeLog in

Frequently asked

5 questions

Which parts make up a simple electric circuit?

A battery, a bulb, a switch and connecting wires. The battery is the energy source; the bulb turns electrical energy into light (and heat); the switch opens or closes the path; the wires are the conducting path the current flows through.

Why might the bulb not light up?

Most likely the circuit is open somewhere: the switch may be open, a wire may be broken or a connection may be loose. A flat battery or a blown bulb are also possible. The current needs an unbroken loop from one end of the battery back to the other.

What does a switch do?

When the switch is closed the path is complete and current flows; when it is open the path is broken and the bulb goes out. A switch does not make electricity; it only opens and closes the path.

Why does a battery run out?

The substances inside a battery take part in chemical reactions that supply electrical energy. As the substances that can still react get used up, the battery cannot give the circuit enough energy and the bulb grows dim.

Can I do these experiments with a wall socket?

No. Mains electricity from a socket (about 100 to 240 volts, depending on the country) is very dangerous. Do circuit experiments only with low-voltage batteries or in a simulation, and never put anything into a socket.