openelectronics

Interactive instruments and first-principles learning pages for electrical and electronics engineering.

Open Circuit Lab

Five instruments: RLC and phasors, Bode plots, a Smith chart, diode and MOSFET curves, and buck and boost converters. Direct links: RLC · Bode · Smith · Devices · DC-DC

Photonics

Electromagnetics and Maxwell
From Maxwell's equations to waves, reflection and the skin effect - the physics under every antenna, waveguide and chip wire. A first-principles learning page.
Fresnel equations from Maxwell's boundary conditions: p-polarised light is not reflected at the Brewster angle.
Notes (.md) · Full page
Silicon photonics waveguides
How light is guided on a chip - slab and wire waveguides, ring resonators and optical interconnects. A first-principles learning page.
Through-port dip of an all-pass ring: the depth depends on how the coupling r compares with the round-trip loss a; resonances repeat every FSR.
Notes (.md) · Full page
Lasers and photodetectors
How semiconductors make light and detect it - LEDs, laser diodes, photodiodes and solar cells. A first-principles learning page.
Responsivity rises with wavelength (more photons per watt) until the band gap sets a hard long-wavelength cutoff; illustrative eta = 0.8.
Notes (.md) · Full page

Chips and devices

IC fabrication flow
How a chip is made, from a bare silicon wafer to a packaged die - oxidation, lithography, etching, doping, deposition, polishing and yield. A first-principles learning page.
Deal-Grove: growth is linear at first (reaction-limited) and slows to parabolic (diffusion-limited) as the oxide thickens.
Notes (.md) · Full page
Lithography and EUV limits
Why printing smaller chips needs shorter light and bigger lenses - Rayleigh resolution, depth of focus, EUV and photon shot noise. A first-principles learning page.
Resolution improves with shorter wavelength and larger NA; the dots mark typical tool settings (idealised, single exposure).
Notes (.md) · Full page
MOSFET and CMOS scaling
How the transistor works and why shrinking it helped, then stopped helping - square-law operation, subthreshold leakage and Dennard scaling. A first-principles learning page.
Square-law model: a resistor-like triode region below V_GS - V_T, then a flat saturation current.
Notes (.md) · Full page
VLSI circuit design
From a single CMOS inverter to a chip - logic levels, noise margin, dynamic power, the energy-delay trade-off and the digital design flow. A first-principles learning page.
A CMOS inverter flips sharply near V_DD/2, restoring logic levels, and draws current only while switching.
Notes (.md) · Full page

Power, RF and sensing

Power electronics converters
How switching converters change voltage efficiently - buck, boost and buck-boost, inductor ripple, losses and wide-bandgap devices. A first-principles learning page.
The inductor ramps up while the switch is on and down while it is off; the ripple is set by L and the switching frequency.
Notes (.md) · Full page
RF, antennas and microwaves
Transmission lines, reflection and matching, antennas and the Friis link budget - how radio signals travel and how circuits hand them over. A first-principles learning page.
Friis free-space loss grows 20 dB per decade of distance and with frequency, which is why mmWave needs high-gain antennas.
Notes (.md) · Full page
Sensors, MEMS and control
How tiny mechanical sensors work and how feedback makes systems behave - MEMS resonators, capacitive sensing and PID control. A first-principles learning page.
A mass-spring-damper is the model for most MEMS: a high Q gives a tall, narrow resonance, ideal for sensing small shifts.
Notes (.md) · Full page

Learning pages with standard textbook formulas and illustrative component values. Not for design sign-off.

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