NEIEP Mechanics Practice Exam

How should ohmmeters be configured to take measurements in a circuit?

1. Connected in series with the load

2. Disconnected from the circuit

3. Connected in parallel across the load with one lead disconnected

4. Placed near the circuit without connection

The correct answer is: Connected in parallel across the load with one lead disconnected

For accurate resistance measurements, ohmmeters must be connected in parallel across the component or load in question. By connecting in parallel, you allow the ohmmeter to measure the resistance of the component directly without introducing additional resistance into the circuit that would alter the reading. When an ohmmeter is hooked up in parallel, it applies a small voltage across the terminals, enabling it to calculate the resistance based on the current flowing through the circuit. As a result, this configuration provides a precise reading of how much resistance exists in the specific part of the circuit being tested. Connecting the ohmmeter in series, as in one of the options, would lead to inaccurate measurements because the meter would become part of the circuit, thus affecting the overall circuit behavior and its resistance. Similarly, disconnecting the circuit before measurement or placing the meter without connection does not provide any context or functionality for measuring resistance, rendering those options ineffective.