What is the difference between a voltmeter and an ammeter?

• A. A voltmeter measures current; an ammeter measures voltage.
• B. A voltmeter measures resistance; an ammeter measures power.
• C. A voltmeter measures voltage; an ammeter measures current.
• D. A voltmeter measures frequency; an ammeter measures impedance.

Answer: (C)

The main idea here is understanding what each meter measures and how to place it in a circuit. A voltmeter measures voltage—the potential difference between two points. To measure this without disturbing the circuit, it’s connected in parallel with the component, and it has high internal resistance so it draws only a tiny current. An ammeter measures current—the rate of flow of electric charges. It must be placed in series with the circuit so all the current flows through it, and it has very low resistance to avoid dropping much voltage and changing the current.

So, the correct description is that a voltmeter reads voltage and an ammeter reads current. The other statements describe measuring resistance or power, or refer to properties like frequency or impedance, which are not what these meters are designed to measure.