A voltmeter is used to measure which electrical quantity?

A voltmeter is used to measure which electrical quantity?

• A. Current
• B. Voltage
• C. Resistance
• D. Frequency

Answer: (B)

Measuring electrical potential difference between two points is what the voltmeter is designed for. A voltmeter reads the voltage across a component or across a portion of a circuit, and it’s connected in parallel so it measures without forcing current through the part under test. Its high input impedance minimizes the load on the circuit, keeping the original voltages intact. If it were placed in series, it would alter the current and give a distorted reading. In contrast, current is measured with an ammeter placed in series to sense the flow of electrons, resistance is determined with an ohmmeter when the circuit is de-energized, and frequency is measured with a frequency counter or oscilloscope, not a basic voltmeter.

Measuring electrical potential difference between two points is what the voltmeter is designed for. A voltmeter reads the voltage across a component or across a portion of a circuit, and it’s connected in parallel so it measures without forcing current through the part under test. Its high input impedance minimizes the load on the circuit, keeping the original voltages intact. If it were placed in series, it would alter the current and give a distorted reading. In contrast, current is measured with an ammeter placed in series to sense the flow of electrons, resistance is determined with an ohmmeter when the circuit is de-energized, and frequency is measured with a frequency counter or oscilloscope, not a basic voltmeter.