Engineer Maha Mohammed explains that since human senses cannot perceive the flow of electrical charges, the multimeter acts as a tool that transforms this mystery into tangible numbers, allowing us to understand what happens inside wires and silent electronic components. Electricity, at its core, relies on three interacting forces: voltage, which represents the driving force; current, which represents the quantity of moving charges; and resistance, which expresses the impedance of the path to the passage of these charges. Controlling these elements is what allows devices to operate efficiently or protects them from burning out. To translate these concepts into a visible reality, the multimeter is used for three main functions: 1. Measuring voltage (electrical pressure): The device is set to voltage mode, and the probes are placed at the terminals of the source or component to be tested. In this case, the device simply reads the "force difference" between the two points, indicating whether the battery has sufficient power or if the socket is supplying the device with the required voltage to operate. 2. Measuring current (flow rate): This process is the most accurate, as the entire current must pass through the device itself. The multimeter is set to amperage mode, and the electrical circuit is opened, making the device part of the path. Here, the multimeter acts as a counter, counting the amount of charge passing through the wire, thus revealing the device's power consumption. 3. Resistance Measurement and Continuity Testing: The device uses its internal battery to test the resistance to current flow in a particular material. The "continuity" feature is the fastest way to see "behind the wires." As soon as the "beep" sounds, you can be sure that the copper conductor is connected and not broken, even if the outer plastic casing appears perfectly intact. By relying on multimeter readings, complex faults can be diagnosed simply by observing the change in the numbers. A sudden drop in power or an interruption in current are silent signals that indicate a technical malfunction before it worsens and leads to device damage. Al-Mustaqbal University, the leading university in Iraq.