### Voltage (V)

Voltage is the difference in electric potential between two points in a circuit. The driving force pushes electric charges to move through a conductor. Higher voltage levels indicate a greater potential difference, leading to a stronger force pushing the electrons. Voltage is essential for the operation of electrical devices, as it determines the energy supplied to them.

### Current (I)

Current is the flow of electric charge through a conductor, measured in amperes (A). It represents the movement of electrons through a circuit, driven by the voltage difference. The current flow depends on the voltage and the resistance in the circuit. Proper control of current is crucial in electrical systems to prevent overheating and damage to components.

### Resistance (R)

Resistance is the opposition to the flow of electric current in a material, measured in ohms (Î©). Collisions between electrons and atoms within the conductor cause it. Higher resistance means less current flow for a given voltage, as the material hinders the movement of electrons. Managing resistance is vital in designing circuits to ensure efficient operation and prevent energy loss.

### Power (P)

Power is the rate at which electrical energy is transferred or consumed in a circuit, measured in watts (W). It is calculated as the product of voltage and current (P = VI). Electrical power determines how much work can be performed by an electrical device in a given time. Efficient power management is crucial for energy conservation and reducing operational costs in electrical systems.

### Capacitance (C)

Capacitance is the ability of a component or circuit to store electrical charge, measured in farads (F). Capacitors store energy in an electric field created between two conductive plates separated by an insulator. They release this energy when needed, making them essential for smoothing out voltage fluctuations and maintaining power supply stability. Capacitors are widely used in filtering, timing, and energy storage applications.

### Inductance (L)

Inductance is the property of a conductor or coil that opposes changes in current flow, measured in henries (H). Inductors store energy in a magnetic field created by the current passing through them. When the current changes, the magnetic field induces a voltage that opposes the change, thereby regulating the current flow. Inductance is fundamental in designing transformers, motors, and various signal-processing circuits.

### Impedance (Z)

Impedance is a circuit’s total opposition to the flow of alternating current (AC), measured in ohms (Î©). It combines both resistance and reactance (capacitive and inductive) and varies with frequency. Impedance matching is critical in AC circuit design to ensure maximum power transfer and minimize signal reflection. Understanding impedance is essential for designing efficient and reliable AC systems.

### Frequency (f)

Frequency is the number of cycles a periodic electrical signal completes in one second, measured in hertz (Hz). It determines the rate at which the signal oscillates and is a fundamental characteristic of AC signals. Higher frequencies are used in communication systems, while lower frequencies are typical in power transmission. Proper frequency control is essential for the stability and performance of electrical and electronic systems.

### Reactance (X)

Reactance is the opposition to the change in current flow caused by inductance and capacitance in an AC circuit, measured in ohms (Î©). It varies with the frequency of the AC signal, unlike resistance, which is constant. Inductive reactance increases with frequency, while capacitive reactance decreases. Managing reactance is crucial for designing circuits that operate efficiently at specific frequencies.

### Transformer

A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It consists of primary and secondary windings wound on a magnetic core. Transformers are used to step up or down voltage levels in power transmission, enabling efficient long-distance electricity distribution. They play a vital role in adjusting the voltage to safe levels for household and industrial use.