A device which is used to break or make an electric circuit is called [[1]]. 

We can solve this problem in the sense of current power outages. The circuit has many components to be a complete circuit. Must have ammeter, voltmeter, resistance to switch. The ammeter and voltmeter are series and correspond to the circuit respectively. The current ratio, voltage, and resistivity ratio in a circuit can be defined by Ohm's law as follows. Where voltage, current, resistance. When current flows in one cycle, the temperature of the wire rises, which becomes a big problem. This area can be destroyed by rising temperatures. A switch is an electrical device that can cut off conductors, connect electrical circuits, interfere with energy, and redirect energy from one direction to another.
Therefore, the switch is a device for breaking or creating a circuit. When you press the "OPEN" button, the circuit is called a completely open circuit and current flows through the circuit. If the switch is in the closed range, the circuit is incomplete and is called a closed circuit, with no current flowing through the cycle.
Thus, the correct answer is switch.