11.5.C—Describe the measurement of current and potential difference in a circuit

Describe the measurement of current and potential difference in a circuit.

• Ammeters are used to measure current at a specific point in a circuit.
  • i. Ammeters must be connected in series with the element in which current is being measured.
  • ii. Ideal ammeters have zero resistance so that they do not affect the current in the element that they are in series with.
• Voltmeters are used to measure electric potential difference between two points in a circuit.
  • i. Voltmeters must be connected in parallel with the element across which potential difference is being measured.
  • ii. Ideal voltmeters have infinite resistance so that no charge flows through them.
• Nonideal ammeters and voltmeters will change the properties of the circuit being measured. BOUNDARY STATEMENT Unless otherwise stated, all batteries, wires, and meters are assumed to be ideal. Circuits with batteries of different potential differences connected in parallel will not be assessed.