Electric Current and Circuit Components
This page introduces fundamental concepts of electricity and circuit components. It covers the basics of electric current, resistance, and circuit elements.
Definition: Electric current is the flow of electric charge, typically carried by moving electrons in a conductor.
The direction of conventional current is from positive to negative, opposite to the flow of electrons. Key circuit components discussed include resistors, switches, and diodes.
Vocabulary: Ampere A - The unit of electric current, measuring the amount of electric charge passing a point in an electric circuit per unit time.
The relationship between current I, charge Q, and time t is given by the formula:
I = Q / t
Example: A circuit passes 6 x 10^-3 C of charge in 0.2 seconds. The current is calculated as:
I = 6 x 10^-3 C / 0.2 s = 3 x 10^-2 A = 0.03 A
The page also introduces the concept of resistance, which opposes the flow of electric current.
Definition: Resistance R is the opposition that a material offers to the flow of electric current. It is measured in ohms Ω.
The resistance of a conductor depends on its length, cross-sectional area, and the material's resistivity. The relationship is given by:
R = ρL / A
Where ρ is the resistivity, L is the length, and A is the cross-sectional area.