What is impedance in electrical terms?

Impedance is defined as the total opposition that an electrical circuit presents to alternating current (AC). It combines both resistance and reactance. Resistance is the component of impedance that opposes the flow of current and is measured in ohms. Reactance, on the other hand, arises from the presence of capacitors and inductors in a circuit, which cause the current to lag or lead the voltage, thereby affecting how AC flows.

When studying circuits, understanding impedance is crucial because it encapsulates the effects of both the resistance and the reactive components on the behavior of AC circuits. This holistic view allows engineers and technicians to analyze circuit performance accurately, especially since AC behavior can be quite complex compared to direct current (DC) systems.

The other options provided do not correctly define impedance. While electrical potential relates to voltage, it does not encompass the concept of opposition to current. The speed of current flow, which can be associated with the rate of charge movement, is not directly related to impedance at all. Additionally, the distinction between AC and DC currents focuses on different aspects of current types rather than the concept of impedance itself.