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First-year EE · DC circuits to machines

Circuits & Electrical Power

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DC Circuit Foundations

  • L1
    Reading the nameplate
    volts, amps, ohms, watts, coulombs — the unit names the quantity
    ★★★★★
    Start
  • L2
    Ohm's Law
    V = IR, asked every way
    ★★★★★
    Start
  • L3
    Charge in motion
    Q = It · current is charge per second
    ★★★★★
    Start
  • L4
    Power, three ways
    P = VI, I²R or V²/R — pick by what the problem gives
    ★★★★★
    Start
  • L5
    Series and parallel
    sum, or product over sum — and the rail that catches a swapped rule
    ★★★★★
    Start
  • L6
    Dividers
    where the volts and the amps go — and which resistance sits on top
    ★★★★★
    Start
  • L7
    The real wire
    R = ρL/A, corrected for temperature
    ★★★★★
    Start
  • ★
    The Breadboard Final
    the boss · no calculator · one circuit, worked line by line
    ★★★★★
    Start

Kirchhoff & the Network Theorems

  • L9
    The loop rule
    voltages around any closed loop sum to zero
    ★★★★★
    Start
  • L10
    The node rule
    currents into a node sum to currents out
    ★★★★★
    Start
  • L11
    Two laws together
    KVL and KCL on one circuit, with the divider as the shortcut
    ★★★★★
    Start
  • L12
    Thevenin from two readings
    R_Th from an open-circuit and a loaded measurement
    ★★★★★
    Start
  • L13
    Norton and the matched load
    the current-source twin, and the load that takes the most power
    ★★★★★
    Start
  • L14
    Delta to wye and back
    the transformation that unlocks bridge networks
    ★★★★★
    Start
  • L15
    Design the drop
    size the series resistor an LED actually needs — and pick the part
    ★★★★★
    Start
  • ★
    The Black Box Final
    the boss · no calculator · two readings to a full equivalent
    ★★★★★
    Start

Storage & AC Impedance

  • L17
    Capacitance
    C = Q/V, and the ½CV² a charged capacitor is holding
    ★★★★★
    Start
  • L18
    Capacitor combinations
    series and parallel — the resistor rules, flipped
    ★★★★★
    Start
  • L19
    RC transients
    τ = RC, and the exponential road to zero
    ★★★★★
    Start
  • L20
    Inductors
    τ = L/R, and the energy in the field
    ★★★★★
    Start
  • L21
    RMS and peak
    the √2 between what the meter reads and what the wave does
    ★★★★★
    Start
  • L22
    Reactance
    X_L climbs with frequency, X_C falls — and why
    ★★★★★
    Start
  • L23
    Impedance
    Z from R and X — Pythagoras on the impedance triangle
    ★★★★★
    Start
  • L24
    Resonance
    f₀, the Q that sharpens it, the bandwidth it sets
    ★★★★★
    Start
  • L25
    Filters and decibels
    the −3 dB corner, and gains measured in dB
    ★★★★★
    Start
  • ★
    The Resonance Bench
    the boss · no calculator · tune it, sharpen it, band it
    ★★★★★
    Start

AC Power & the Bill

  • L27
    Power factor
    P = VI cos φ · the watts you get from the amps you draw
    ★★★★★
    Start
  • L28
    The power triangle
    kW, kvar and kVA — the right triangle every plant lives on
    ★★★★★
    Start
  • L29
    Three-phase power
    the √3 that turns line quantities into power
    ★★★★★
    Start
  • L30
    Wye and delta systems
    line versus phase — which quantity carries the √3
    ★★★★★
    Start
  • L31
    Power-factor correction
    the kvar of capacitors that buys the utility's forgiveness
    ★★★★★
    Start
  • L32
    The meter
    E = Pt in kilowatt-hours, priced at the utility rate
    ★★★★★
    Start
  • L33
    Feeders and voltage drop
    volts lost in the run, and the percent the code allows
    ★★★★★
    Start
  • L34
    Battery runtime
    Peukert's correction to the amp-hour promise
    ★★★★★
    Start
  • ★
    The Utility Audit
    the boss · no calculator · from load to invoice
    ★★★★★
    Start

Motors, Transformers & Generators

  • L36
    Synchronous speed and slip
    120f/p, and the few percent an induction motor gives back
    ★★★★★
    Start
  • L37
    Torque from power
    T = P/2πN · what a rated motor twists with at speed
    ★★★★★
    Start
  • L38
    Motor efficiency
    shaft watts out over line watts in — and what the line must carry
    ★★★★★
    Start
  • L39
    Nameplate currents
    full-load amps, and the inrush at locked rotor
    ★★★★★
    Start
  • L40
    Transformers
    turns ratio sets the volts; the nameplate sets the amps
    ★★★★★
    Start
  • L41
    Sag and fault
    one nameplate %Z, read at both extremes of loading
    ★★★★★
    Start
  • L42
    Generator sizing
    the kW a connected load actually demands of its standby set
    ★★★★★
    Start
  • ★
    The Machine Room Final
    the boss · no calculator · one motor, read end to end
    ★★★★★
    Start

Electromagnetics Basics

  • L44
    Coulomb's Law
    the inverse square — and the millionths that come with it
    ★★★★★
    Start
  • L45
    A charge in a magnetic field
    F = qvB sin θ · stand still and nothing happens
    ★★★★★
    Start
  • L46
    Wires and forces
    the motor effect, and the pull two busbars trade
    ★★★★★
    Start
  • L47
    The solenoid
    turns per metre, not turns — the whole lesson in one distinction
    ★★★★★
    Start
  • L48
    Flux and Faraday
    count the flux first, then price how fast it changes
    ★★★★★
    Start
  • L49
    Motional EMF
    ε = BLv · one bar, two rails, and every generator ever built
    ★★★★★
    Start
  • ★
    The Induction Gauntlet
    the boss · no calculator · field, flux, EMF, in one pass
    ★★★★★
    Start

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