Fill in the blanks .
A device that is used to break an electric circuit is called________ .

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a device that is used to break an electric circuit. This means we need to identify a component that can interrupt the flow of electricity in a circuit.

2. **Identifying the Device**: In electrical circuits, there are several components, but the one specifically designed to open or close a circuit is known as a "switch."

3. **Explaining the Function of a Switch**: A switch can either allow current to flow (closed circuit) or stop the current from flowing (open circuit). When the switch is in the "off" position, it breaks the circuit, preventing electricity from flowing. Conversely, when the switch is in the "on" position, it completes the circuit, allowing current to flow.

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