| Symbol | Function |
 | A key is used to put the current on and off in a circuit |
 | A cell acts as a source of direct current for the circuit. |
 | It controls the flow of current in a circuit. |
 | An ammeter is an instrument used to measures the magnitude of current flowing in a circuit. |
 | A voltmeter is used to measure the potential difference between two points of a circuit. |
