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Electromagnetism & Electronics

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Electromagnetism & Electronics

Faraday's Law of Induction

Maxwell's third equation stating that a time-varying magnetic flux through a closed conductive loop induces an electromotive force (EMF)…

E = -dΦ_B / dt, ∇ × E = -∂B/∂t V (Volts)
Electromagnetism & Electronics

Ferromagnetism

A strong magnetic phenomenon in which atomic magnetic moments spontaneously align parallel into localized magnetic domains, producing…

μ_r ≫ 1 (μ_r ~ 1,000–100,000) Dimensionless
Electromagnetism & Electronics

Gauss's Law for Electricity

Maxwell's first equation stating that the net electric flux through any closed Gaussian surface equals the total enclosed charge divided by…

Φ_E = ∮ E · dA = Q_enclosed / ε₀, ∇ · E = ρ / ε₀ N·m²/C (or V·m)
Electromagnetism & Electronics

Gauss's Law for Magnetism

Maxwell's second equation stating that the total magnetic flux passing through any closed surface is always identically zero.

Φ_B = ∮ B · dA = 0, ∇ · B = 0 Wb (Webers)
Electromagnetism & Electronics

Hall Effect

The production of a transverse electric potential difference (Hall voltage) across a current-carrying conductor in an orthogonal magnetic…

V_H = (I B) / (n q t), R_H = 1 / (n q) V (Hall Voltage), m³/C (Hall Coefficient)
Electromagnetism & Electronics

Inductive Reactance

The opposition offered by an inductor to alternating current flow, directly proportional to AC frequency and inductance.

X_L = 2π f L = ω L Ω (Ohms)
Electromagnetism & Electronics

Joule Heating

The process in which the flow of electric current through a conductor generates thermal energy due to electrical resistance.

H = I² R t = P t J (Joules)
Electromagnetism & Electronics

Kirchhoff's Laws

Two fundamental circuit analysis laws expressing conservation of electric charge (Current Law) and conservation of energy (Voltage Law).

KCL: ∑ I_in = ∑ I_out; KVL: ∑ V = 0 A (Current), V (Voltage)
Electromagnetism & Electronics

LC Circuit & Oscillations

An electrical circuit containing an inductor and capacitor that exchanges energy periodically between the electric field of the capacitor…

f₀ = 1 / (2π √(L C)), E_total = ½ C V² + ½ L I² Hz (Frequency), J (Energy)
Electromagnetism & Electronics

Lenz's Law

A physical law asserting that the direction of an induced current always produces a magnetic field that opposes the change in magnetic flux…

Represented by the negative sign in E = -dΦ_B/dt Dimensionless (Directional Law)
Electromagnetism & Electronics

Logic Gates

Elementary digital electronic building blocks that perform Boolean logical operations on one or more binary inputs to yield a single binary…

AND: Y = A·B; OR: Y = A + B; NOT: Y = Ā; NAND: Y = (A·B)̄ Binary (0 or 1)
Electromagnetism & Electronics

Lorentz Force

The combined force exerted on a charged particle moving through electromagnetic fields containing both electric and magnetic field…

F = q (E + v × B) N (Newtons)
Electromagnetism & Electronics

Magnetic Dipole

The basic magnetic structure created by a closed circulating current loop or intrinsic particle spin, possessing North and South magnetic…

μ = I A, τ = μ × B A·m² (or J/T)
Electromagnetism & Electronics

Magnetic Dipole Moment

A vector quantity determining the torque experienced by a magnetic dipole when placed in an external magnetic field.

μ = I A, U = -μ · B A·m² (or J/T)
Electromagnetism & Electronics

Magnetic Field

A vector field generated by moving electric charges, electric currents, or intrinsic magnetic moments that exerts magnetic forces on other…

F_mag = q (v × B), B = μ₀ I / (2π r) T (Tesla = N/(A·m))
Electromagnetism & Electronics

Magnetic Flux

The measure of the total magnetic field passing normally through a specified surface area.

Φ_B = ∫ B · dA = |B| |A| cos θ Wb (Webers = T·m²)
Electromagnetism & Electronics

Magnetic Hysteresis

The lagging of magnetization behind the applied magnetizing field in ferromagnetic materials during cyclic magnetization.

Hysteresis Loss Area = ∫ H dB J/m³ (Joules per cubic meter)
Electromagnetism & Electronics

Magnetic Permeability

A material property measuring the degree to which a medium supports and concentrates magnetic flux inside itself when subjected to a…

μ = B / H = μ_r μ₀, μ₀ = 4π × 10⁻⁷ T·m/A H/m (or T·m/A)
Electromagnetism & Electronics

Magnetic Susceptibility

A dimensionless material property measuring the degree of magnetization induced in a material per unit applied magnetic field strength.

M = χ_m H, μ_r = 1 + χ_m Dimensionless
Electromagnetism & Electronics

Maxwell's Equations

The set of four fundamental partial differential equations that unify electricity, magnetism, and optics into classical electrodynamics.

∇·E = ρ/ε₀, ∇·B = 0, ∇×E = -∂B/∂t, ∇×B = μ₀J + μ₀ε₀∂E/∂t Various SI Units
Electromagnetism & Electronics

MOSFET

A Metal-Oxide-Semiconductor Field-Effect Transistor that uses an insulated gate voltage to control current flow through an underlying…

I_D = ½ μ_n C_ox (W/L) (V_GS - V_th)² A (Current)
Electromagnetism & Electronics

Moving Coil Galvanometer, Ammeter & Voltmeter

An electromechanical instrument that measures small currents using magnetic torque on a pivoted coil, converted to an ammeter or voltmeter…

τ = N I A B = k θ; Ammeter: S = I_g G / (I - I_g); Voltmeter: R_s = (V / I_g) - G A (Current), V (Voltage)
Electromagnetism & Electronics

Mutual Inductance

The induction of an electromotive force in a secondary circuit loop caused by a time-varying current in an adjacent primary circuit loop.

E₂ = -M (dI₁/dt), M = k √(L₁ L₂) H (Henries)
Electromagnetism & Electronics

Ohm's Law

An empirical relation stating that the electric current flowing through an ohmic conductor is directly proportional to the applied voltage…

V = I R, J = σ E V = A · Ω