Which characteristic differentiates an ammeter from an ohmmeter?

An ammeter is specifically designed to measure the flow of electric current in a circuit, typically expressed in amperes. This instrument works by being placed in series with the circuit, allowing it to monitor the amount of current flowing through the circuit components. On the other hand, an ohmmeter serves a different purpose; it is used to measure the resistance of an electrical component or circuit, expressed in ohms.

The characteristic that differentiates an ammeter from an ohmmeter is that an ohmmeter cannot measure current because it is calibrated to measure resistance, not current flow. When using an ohmmeter, the measurement requires the circuit to be de-energized, meaning no current is flowing. In contrast, an ammeter requires a live circuit to measure the current accurately.

This distinction in function is crucial in practical applications, as both instruments play vital roles in troubleshooting and testing circuits but are utilized for distinctly different measurements. Understanding this characteristic helps technicians choose the appropriate tool for their diagnostic tasks.