Which of the following meters must use internal power to check a load or circuit?

Which of the following meters must use internal power to check a load or circuit?

• A. Volt meter
• B. Ammeter
• C. Ohmmeter
• D. Multimeter

Answer: (C)

An ohmmeter must use internal power to check a load or circuit because it measures resistance by passing a small current through the component and measuring the voltage across it. This internal power source is essential for the ohmmeter to function correctly, as it allows the device to establish the necessary current flow for measuring how much opposition the load provides to electrical flow. In contrast, a voltmeter measures potential difference across two points in a circuit without requiring internal power since it operates on voltage present in the circuit. An ammeter measures the current flowing through a circuit and typically requires a low resistance path, but it often can measure current without needing internal power if connected in the right circuit configuration. A multimeter can function as either a voltmeter or an ammeter and will also use its internal power only when measuring resistance or in certain configurations. Thus, it's the unique requirement of the ohmmeter to have an internal power source that distinguishes it in this context.

An ohmmeter must use internal power to check a load or circuit because it measures resistance by passing a small current through the component and measuring the voltage across it. This internal power source is essential for the ohmmeter to function correctly, as it allows the device to establish the necessary current flow for measuring how much opposition the load provides to electrical flow.

In contrast, a voltmeter measures potential difference across two points in a circuit without requiring internal power since it operates on voltage present in the circuit. An ammeter measures the current flowing through a circuit and typically requires a low resistance path, but it often can measure current without needing internal power if connected in the right circuit configuration. A multimeter can function as either a voltmeter or an ammeter and will also use its internal power only when measuring resistance or in certain configurations. Thus, it's the unique requirement of the ohmmeter to have an internal power source that distinguishes it in this context.