Electric Circuits and Dipoles

Flashcards covering key vocabulary and concepts related to electric dipoles, circuits, current, resistance, and Kirchhoff's Rules.

Current

The motion of charge from one region to another, defined as I = dQ/dt.

Conventional Current

A current that is treated as a flow of positive charges.

Resistivity

The ratio of the electric field in a material to the current density it causes: 𝜌 = E/J.

Conductivity

The reciprocal of the resistivity.

Resistance of a Conductor

R = 𝜌L/A

Ohm's Law

V = IR. If V is directly proportional to I (R is constant).

Electromotive Force (EMF)

Makes current flow in a circuit; it is not a force.

Real Sources of EMF

Contains some internal resistance r.

Terminal Voltage of an EMF Source

Vab = Ɛ – Ir

Junction

A point where three or more conductors meet.

Loop

Any closed conducting path.

Kirchhoff’s Junction Rule

The algebraic sum of the currents into any junction is zero: ΣI = 0.

Kirchhoff’s Loop Rule

The algebraic sum of the potential differences in any loop must equal zero: ΣV = 0.

Power (P = VabI)

The rate at which energy is delivered to (or extracted from) a circuit element.