SkyDrill

Voltmeter connection in a circuit

Aviation Mechanic General (AMG) practice question 33 of 41 on Fundamentals of Electricity and Electronics. ACS element AM.I.A.K9a · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONA mechanic wants to measure the voltage across a resistor in an operating circuit. How should the voltmeter be connected?

  1. AIn parallel with the resistor
  2. BIn series with the resistor
  3. CIn series between the source and the load
Show the answer and explanation

Correct answer: A. In parallel with the resistor

  • A — correct Voltmeters are connected in parallel with the circuit, across the two points whose potential difference is to be measured.
  • B — incorrect Series connection is used for an ammeter, which measures current; a voltmeter is placed across the component, not in line with it.
  • C — incorrect Placing the meter in line with the source is an ammeter connection; a voltmeter's high resistance would nearly stop the circuit current.

BACKGROUND

A voltmeter uses the same basic meter movement as an ammeter but with a multiplier resistance in series so that it can be placed across a voltage. When voltmeters are used, they are connected in parallel with the circuit. If the voltage is unknown, the first reading is taken on the high range and the range is then reduced until a suitable reading is obtained, and polarity must be observed before connecting. Because a voltmeter shunts some current, a high-resistance voltmeter should be used so that it does not lower the effective resistance of the circuit and change the reading.

STUDY TIP

Voltmeter across, ammeter in line: a voltmeter goes in parallel, an ammeter in series.

KEY POINTS

  • Voltmeters are connected in parallel with the circuit.
  • Start on the high range and work down when the voltage is unknown.
  • Use a high-resistance voltmeter to avoid shunting the circuit.

SOURCES

  • FAA-H-8083-30B ch12 "Voltmeter Circuit Connections"; "Influence of the Voltmeter in the Circuit"
Practice the Aviation Mechanic General (AMG) test →Timed 60-question exam, by ACS area, or review your misses. Free.
MORE ON FUNDAMENTALS OF ELECTRICITY AND ELECTRONICS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.