Potential difference.
What drives charge?
Voltage represents energy difference per unit charge.
Side 52
Electrical
Engineering
A study of systems built from charge, fields and signals. Electrical engineering connects circuits, electronics, electromagnetics, power and control across scales from sensors to grids.
charge→circuit→signal→power→control
06core domains
05circuit ideas
05signal questions
52Side
Circuits constrain how charge and energy move.
Voltage, current and impedance provide a compact language for interconnected electrical elements.
Rate of charge flow.
How much moves?
Current connects circuit behavior to time.
Opposition to current.
V = IR.
Resistive elements dissipate electrical energy as heat.
Capacitors and inductors store energy.
Electric or magnetic field?
Energy storage creates dynamic circuit behavior.
Kirchhoff laws connect elements.
Conservation at nodes and loops.
Current and voltage balances solve complex circuits systematically.
Signals carry information through time and frequency.
Electrical systems often become easier to understand when the same waveform is viewed in multiple domains.
How does the signal change moment to moment?
Useful for transients and waveform shape.
Which oscillatory components are present?
Fourier analysis decomposes signals into frequencies.
Select frequencies.
Low-pass, high-pass and band-pass filters shape signal content.
Turn continuous time into discrete values.
Sampling rate must be high enough to represent the relevant bandwidth.
Unwanted variation contaminates measurement.
Signal-to-noise ratio limits detection and estimation quality.
Embed information in a carrier.
Amplitude, frequency or phase can be varied for communication.
Electronics controls current with devices.
Semiconductor components make amplification, switching, logic and computation possible.
Directional conduction.
Diodes rectify, protect and shape signals through nonlinear current-voltage behavior.
Controlled current or voltage device.
Transistors act as amplifiers or switches.
Increase signal magnitude.
Gain must be balanced against bandwidth, noise and stability.
Physical implementation of Boolean operations.
Digital systems build complex computation from switching networks.
Analog to digital conversion.
Sampling and quantization connect physical signals to computation.
Switch power efficiently.
Converters control voltage, current and frequency with semiconductor switches.
Electric and magnetic fields become machines.
Electromagnetic interaction allows electrical energy to produce force and motion—and motion to produce electrical energy.
Electric field
Force per unit charge.
Voltage differences arise from electric potential fields.
Magnetic field
Acts on moving charge.
Currents and magnets create fields that produce force and torque.
Induction
Changing magnetic flux produces voltage.
Faraday’s law underlies transformers and generators.
Motor
Electrical → mechanical.
Electromagnetic torque converts current into rotation.
Generator
Mechanical → electrical.
Rotational energy induces electrical power.
Power systems move energy at scale.
Generation, transformation, transmission and protection must operate as one synchronized network.
| Element | Function | Core variable | Failure concern |
|---|---|---|---|
| Generator | Create electrical power | Voltage, frequency, real/reactive power | Loss of synchronism / trip |
| Transformer | Change voltage level | Turns ratio, flux | Heating / insulation failure |
| Transmission | Move bulk power | Current, impedance, power flow | Overload / instability |
| Protection | Isolate faults | Fault current, timing | Failure to trip or nuisance trip |
| Load | Consume electrical power | Demand profile | Voltage/frequency stress |
Electrical engineering becomes systems engineering quickly.
Sensors, computation, power stages and control loops must cooperate across interfaces.
Sense
Convert physical state into an electrical signal.
Condition
Filter, amplify and protect the signal.
Compute
Estimate state or make a decision digitally or analogically.
Actuate
Convert an electrical command into force, light, heat or another physical effect.
Power
Supply all stages within voltage, current and thermal limits.
Fundamentals of Electric CircuitsAlexander & Sadiku · circuits
Microelectronic CircuitsSedra & Smith · electronics
Signals and SystemsOppenheim & Willsky · signal analysis
Electric Machinery FundamentalsChapman · motors and generators