Ammeter

Definition

An ammeter is an instrument used to measure the electric current in a circuit. It is typically connected in series with the circuit whose current is being measured.

5 Must Know Facts For Your Next Test

1. Ammeters are designed to have very low internal resistance to minimize the voltage drop across them.
2. Ammeter readings are typically given in amperes (A), milliamperes (mA), or microamperes ($\mu$A).
3. For accurate measurements, ammeters should be connected in series with the load.
4. Using an ammeter incorrectly, such as connecting it in parallel, can cause damage to both the instrument and the circuit.
5. Digital ammeters provide a numerical display of current, while analog ammeters use a needle to indicate current on a scale.

Review Questions

• Why must an ammeter be connected in series with the load for accurate measurement?
• What could happen if an ammeter is mistakenly connected in parallel with a circuit element?
• How does the internal resistance of an ammeter affect its operation and measurement accuracy?

Related terms

Voltmeter:

An instrument used for measuring electrical potential difference between two points in a circuit. It is connected in parallel with the component whose voltage is being measured.

Ohmmeter:

A device used to measure electrical resistance within a circuit. It often combines functions of other meters and uses its own power source.

Multimeter: An electronic measuring instrument that combines several measurement functions in one unit, commonly measuring voltage, current, and resistance.