Which statement about voltmeters is accurate?

Which statement about voltmeters is accurate?

• A. It has one lead and measures current.
• B. It measures resistance by bridging two points.
• C. It is inserted in series to measure voltage.
• D. It has two leads and measures voltage between two points.

Answer: (D)

Voltmeters measure the electric potential difference between two points. To do this accurately without significantly loading the circuit, they are connected across the two points—i.e., in parallel—and they have two leads to touch those points. Their high internal resistance helps keep current draw very small, so the circuit’s operation isn’t disturbed. This is why the accurate statement describes a device with two leads that measures voltage between two points. The other descriptions mix up what a voltmeter does: measuring current is what an ammeter does and is placed in series; measuring resistance across two points is an ohmmeter function, not a voltmeter; and a voltmeter is not inserted in series to measure voltage.

Voltmeters measure the electric potential difference between two points. To do this accurately without significantly loading the circuit, they are connected across the two points—i.e., in parallel—and they have two leads to touch those points. Their high internal resistance helps keep current draw very small, so the circuit’s operation isn’t disturbed. This is why the accurate statement describes a device with two leads that measures voltage between two points. The other descriptions mix up what a voltmeter does: measuring current is what an ammeter does and is placed in series; measuring resistance across two points is an ohmmeter function, not a voltmeter; and a voltmeter is not inserted in series to measure voltage.