Electromagnetism & Electronics — 67 Terms Defined

Operational Amplifier (Op-Amp) Electromagnetism & Electronics V (Volts) A high-gain DC-coupled electronic voltage amplifier with differential inputs and single-ended output. V_out = A_OL (V_+ - V_-)

Parallel Circuit Electromagnetism & Electronics Ω (Ohms) An electrical circuit topology in which components are connected across common voltage nodes, offering multiple parallel paths for current. 1 / R_total = (1/R₁) + (1/R₂) + (1/R₃), V_total = V₁ = V₂ = V₃

Paramagnetism Electromagnetism & Electronics Dimensionless (χ_m > 0) A weak form of magnetism in which materials with unpaired electrons are weakly attracted into an external magnetic field. χ_m = C / T (Curie's Law)

Power Factor Electromagnetism & Electronics Dimensionless (0 to 1) The ratio of real power dissipated by an AC circuit to the apparent power delivered by the supply. PF = cos φ = P_real / S_apparent = R / Z

Poynting Vector Electromagnetism & Electronics W/m² (Watts per square meter) A vector representing the directional energy flux density (power per unit area) transported by an electromagnetic field. S = (1 / μ₀) (E × B)

RC Circuit & Time Constant Electromagnetism & Electronics s (Seconds) An electrical circuit composed of resistors and capacitors driven by a voltage source, characterized by its exponential charging and discharging time constant τ. V(t) = V₀ e^(-t / τ), τ = R C

RL Circuit Electromagnetism & Electronics s (Seconds) An electrical circuit containing resistors and inductors, characterized by an exponential delay in current growth and decay governed by time constant τ = L/R. I(t) = (V₀ / R) (1 - e^(-t / τ)), τ = L / R

RLC Circuit & Resonance Electromagnetism & Electronics Hz (Frequency), Ω (Impedance) An electrical circuit containing a resistor, inductor, and capacitor whose total impedance reaches a minimum at the resonant frequency. f_res = 1 / (2π √(L C)), Z = √(R² + (X_L - X_C)²)

RMS Current Electromagnetism & Electronics A (Amperes) The Root-Mean-Square value of an alternating current (AC), representing the equivalent direct current (DC) that delivers equal average heating power to a resistor. I_rms = I_peak / √2 ≈ 0.707 I_peak

Self-Inductance Electromagnetism & Electronics H (Henries = V·s/A) The property of an electrical conductor or coil whereby a change in current induces an opposing electromotive force in the conductor itself. E = -L (dI/dt), L = N Φ_B / I

Semiconductor Diode Electromagnetism & Electronics A (Current), V (Voltage) A two-terminal semiconductor device formed by a p-n junction that allows electric current to flow easily in one direction while blocking it in reverse. I = I_s [exp(e V / (k_B T)) - 1]

Series Circuit Electromagnetism & Electronics Ω (Ohms) An electrical circuit topology in which components are connected end-to-end sequentially along a single continuous current path. R_total = R₁ + R₂ + R₃, I_total = I₁ = I₂ = I₃

Solenoid Electromagnetism & Electronics T (Tesla) A long helical coil of insulated wire that produces a uniform interior magnetic field when an electric current flows through it. B = μ₀ n I (where n = N / L)

Toroid Electromagnetism & Electronics T (Tesla) A doughnut-shaped ring wrapped with insulated wire that confines a uniform magnetic field completely within its circular core. B = (μ₀ N I) / (2π r)

Transformer Electromagnetism & Electronics Dimensionless (Turns Ratio) A static AC electrical device that transfers electrical energy between circuits through mutual electromagnetic induction to step up or step down AC voltage. V_s / V_p = N_s / N_p = I_p / I_s

Voltage Electromagnetism & Electronics V (Volts = J/C) The electric potential difference between two points, defined as the work required per unit charge to move a positive test charge between them. V = W / q = I R

Wattless Current Electromagnetism & Electronics A (Amperes) The component of alternating current that is 90 degrees out of phase with AC voltage, consuming zero net electrical power. I_wattless = I_rms sin φ

Wheatstone Bridge Electromagnetism & Electronics Ω (Ohms) An electrical bridge network consisting of four resistor arms used to measure an unknown electrical resistance with high precision. R_x = R₃ (R₂ / R₁) (when balanced: I_galvanometer = 0)

Zener Diode Electromagnetism & Electronics V (Volts) A heavily doped silicon p-n junction diode designed to operate safely in reverse breakdown mode to maintain a precise reference voltage. V_out = V_Z (constant in reverse breakdown)