Current Electricity Lecture Notes

Vocabulary flashcards covering key concepts from the lecture notes on current electricity, including definitions of electric current, drift speed, current density, and conservation laws.

Electric Current

The movement of charge from one location to another.

Net electric current in a conductor (without electric field)

Zero, due to the free and random movement of electrons in all directions.

Drift speed (vd)

The net motion of electrons in a conductor resulting from the force exerted by an electric field, usually a small number (~10^-4 m/s).

Electron current (ie)

The number of electrons per second that pass through a cross-sectional area (ie = ne / Δt) or defined in terms of drift speed as ie = NeA vd.

Electric current (I)

A generic definition as the rate of charge flow (I = dQ / dt), related to electron current by I = eie.

Ampere (A)

The unit for electric current, defined as 1 Coulomb per second (1 C/s).

Current density (J)

The current per cross-sectional area (J = I / A),

Unit of current density

Ampere per square meter (A/m²).

Conservation of Current

The principle stating that the current is the same at all points in a current-carrying wire, as electrons cannot disappear.

Kirchhoff

Kirchoff's Junction Law.

A law stating that the sum of the current entering a junction equals the sum of the current leaving the junction.

Current density related to drift speed

J = eNevd.