How is amperage measured in an electrical circuit with a DMM?

Amperage, or current, is measured in series when using a Digital Multimeter (DMM) because this configuration allows the multimeter to become part of the circuit. By connecting the DMM in series, it measures the amount of current flowing through the entire circuit at that point. This is essential because current is defined as the flow of electric charge through a conductor, and measuring it in series ensures that you capture the total current flowing.

When measuring amperage using a DMM, you have to break the circuit open at the point where you want to measure the current. The multimeter then completes the circuit, directing all the current through the meter. If the meter were connected in parallel instead, it would provide an incorrect reading because it would not be measuring the current flowing through the circuit and instead would potentially create a short circuit, leading to inaccurate readings or damage to the meter.

Using alternate methods like a clamp-on meter does not involve breaking the circuit but instead provides a non-intrusive way to measure current without disrupting the flow. However, this method is distinct from what is required when using a DMM.