ARRL Technician Practice Exam 2025 - Free Technician License Practice Questions and Study Guide

An ohmmeter is specifically designed to measure resistance in electrical circuits. It operates by applying a small voltage to the resistor being tested and measuring the resulting current, allowing it to calculate the resistance using Ohm's Law (R = V/I). This instrument provides direct readings of resistance in ohms, making it essential for tasks that require assessing the functionality of components like resistors, as well as checking for shorts or open circuits.

In contrast, an ammeter measures the flow of electric current in amperes and is used primarily in series with the circuit under test. A voltmeter is used to measure voltage levels across components and operates in parallel to the circuit. A capacitance meter, on the other hand, is utilized to measure the capacitance of capacitors. Each of these instruments serves distinct purposes in the field of electronics, but only the ohmmeter directly measures resistance.