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Electrical Engineering

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Electrical engineering covers the generation, transmission, and use of electrical energy and the design of analog and digital electronic systems — from microwatt sensors to gigawatt grids.

Overview

The field splits into power (generation, transmission, distribution, motors), electronics (analog, digital, mixed-signal, RF), communications and signals, controls, and computer engineering. Most working engineers specialize in one or two areas but draw on all of them.

Fundamentals

  • Voltage, current, resistance, power — V, I, R, P.
  • AC vs DC — RMS values, frequency, phase, reactive power.
  • Impedance — combined resistance + reactance (Z = R + jX).
  • Three-phase power — wye vs delta, line vs phase quantities.
  • Power factor — cos(φ); correction with capacitor banks.
  • Magnetic circuits — transformers, motors, solenoids.

Core Laws & Formulas

  • Ohm’s law: V = I·R
  • Power: P = V·I = I²·R = V²/R
  • Three-phase power: P = √3 · VL · IL · cos(φ)
  • Kirchhoff: ΣV around loop = 0, ΣI at node = 0
  • Capacitor energy: E = ½ · C · V²
  • Inductor energy: E = ½ · L · I²
  • RC time constant: τ = R·C
  • Resonance: f = 1 / (2π·√(LC))
  • Transformer ratio: Vp/Vs = Np/Ns

Power Systems

US distribution is typically 120/208 V or 277/480 V three-phase wye; industrial loads use 480 V most often. Transmission runs at 69 kV–765 kV. Common motor voltages: 230/460 V (three-phase), 2300/4160 V (medium voltage). Size conductors per NEC Article 310 using ampacity tables and apply derating for ambient temperature and conduit fill.

Electronics

  • Diodes, BJTs, MOSFETs, IGBTs — semiconductor switches.
  • Op-amps (LM358, LM324, TL072) — amplification, filtering, comparison.
  • Microcontrollers (STM32, ESP32, AVR, PIC) and FPGAs (Xilinx, Intel).
  • SMPS topologies — buck, boost, buck-boost, flyback, forward.
  • Signal integrity — impedance matching, decoupling, EMC.

Standards

  • NFPA 70 (NEC) — National Electrical Code.
  • NFPA 70E — electrical safety in the workplace.
  • IEEE 519 — harmonic limits.
  • IEEE 1584 — arc-flash incident energy.
  • IEC 60364 — low-voltage installations.
  • UL 508A — industrial control panels.
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