Voltage (V): Voltage, also known as electric potential difference, is the measure of the potential energy between two points in an electrical circuit. It is the force that pushes electric charges through a conductor and is measured in volts (V). Voltage can be thought of as the pressure that drives electric current through a circuit.
Current (I): Current is the flow of electric charge through a conductor, such as a wire. It is measured in amperes (A) or amps. Electric current results from the movement of electrons, and it flows from a point of higher potential to a point of lower potential. Current can be direct (DC), where the flow of electrons is in one direction, or alternating (AC), where the flow of electrons periodically reverses direction.
Resistance (R): Resistance is a measure of how much a material or component opposes the flow of electric current. It is measured in ohms (Ω). All materials have some resistance, but conductors have low resistance, allowing current to flow easily, while insulators have high resistance, restricting the flow of current. Resistors are components specifically designed to introduce a precise amount of resistance into a circuit.
Power (P): Power is the rate at which electrical energy is transferred by an electric circuit. It is measured in watts (W). Power can be calculated using the formula P = VI, where V is the voltage and I is the current. Power indicates how much work is being done by the electric current, such as lighting a bulb or driving a motor.