​The Path of Electricity: a Circuit

​I. Electricity flows in a path.

• This path is called a circuit.

• ALWAYS starts at the positive input.

  • Electricity (electrons) flow from the positive end through a wire to the output.

  • The output transforms electricity into other forms of energy: light, heat, sound, and mechanical.

    • Then, electricity continues its flow through the wire to the negative end of the circuit.

​II. Every electrical circuit has a positive end and a negative end.

• All batteries have a + end and a – end.

• All plugs have two metal pieces for the same reason. The third metal piece on some plugs helps to protect from shocks.

• Connecting the inputs, wires, and outputs in a circuit in the right order is important, or the circuit will not work.

​III. When a circuit does not work, there are step‐by‐step things to do to check the circuit:

1. Check the battery in a different circuit to make sure it isn’t dead.

2. Check the bulb in a different circuit to make sure it isn’t dead.

3. Check the wires to make sure they are connected correctly: positive, to bulb, back to negative.

4. ​Check to make sure that all connections are clean and wires are touching.

​This sequence of events is called troubleshooting. Most of the time when something doesn’t work, it is because it isn’t plugged in or the wires aren’t connected the right way. Troubleshooting the circuit will identify whether it is the battery, bulb, or connections that are causing the circuit to fail.