What does the "closed circuits" mean?

Native speaker’s answer
Rebecca
A "closed-circuit" is a technical term for a path that an electrical current flows or circulates! You can make it with wires or cables. An "open circuit" would mean that no electricity flows and that the circuit would not be connected. Ex: We made a closed circuit at school today! The light turned on when the wires joined. Ex: There was a closed-circuit connection from my video camera to the TV using a cable.