NEIEP Mechanics Practice Exam

How should voltmeters be connected to measure voltage in a circuit?

1. In series with the load

2. In parallel across the load

3. In series with the power source

4. In parallel with the power source

The correct answer is: In parallel across the load

To measure voltage in a circuit, voltmeters should be connected in parallel across the load. This configuration allows the voltmeter to measure the potential difference (voltage) across the component or section of the circuit of interest, providing an accurate reading of the voltage present. When connected in parallel, the voltmeter can take advantage of the fact that voltage across parallel components is the same. This means it can measure the voltage drop across the load without altering the circuit's overall current. Alternatively, if a voltmeter were connected in series, it would disrupt the current flow in the circuit, leading to incorrect readings and potentially damaging the voltmeter. This principle ensures that the voltmeter functions effectively to provide the necessary voltage readings for circuit analysis and troubleshooting.