This site is a public home for some personal projects of a retired electrical engineer. It is an attempt to document things I find interesting, or that puzzle me, or that I am just curious about.
Most of the entries are circuit simulations using QucsStudio by Michael Margraf, DD6UM, freely available here . Also helpful, especially for digital simulations, is Micro-Cap 12 SPICE by Spectrum Software, freely available here .
Most recent changes / additions:
Added a spreadsheet with links to BibleGateway dot com for the Puritan reading plan (Jan 2025).
"We thank Thee Lord, for happy hearts" (Nov 2024)
Damped oscillation and energy transfer between capacitors (Nov 2024)
Subcircuit for a voltage-controlled switch (Oct 2024)
LC Resonators for oscillators (Oct 2024)
Benchmark Circuits from Spice history (Oct 2024)
3:16 Bible Texts and Donald Knuth's book
Alfred Vail Ciphers solved
Cannonball Puzzle from my father-in-law
Fidelitone and FonoTwin , Dad's dual turntables
"For happy hearts", a prayer before meals
Functions Max Min Atan2
Heathkit , how I got started
Helen Fouche Gains , a notable life of a cryptanalyst
Machine Epsilon , after "Hello World"
Ogee curve formula
Sag and Tension Background , and approximation for Cosh (x)
Sag and Tension Graphing Calculator for suspended wire antennas or cables
Ten-Tec Jupiter encoder control replacement
"The Enciphered Letter" , Russian to English translation
A two-transistor buffer using 2N2222A BJTs.
Benchmark Circuits from Spice history
Class-A and -B RF power amplifiers using an ideal FET.
Class-C power amplifier basics.
Class-E RF power amplifier using an ideal FET.
Class-J RF power amplifier using an ideal FET.
Short-Open-Load Calibration
Measuring the resistance of 3 DC probes
Measuring the gains of 3 microwave antennas
Short-Open-Load calibration of one-port impedance measurements
180 Degree duHamel coupler
Gingell RC Polyphase
AC simulation of a 1967 benchmark
Audio FSK Demodulator, the AEA CP-1 RTTY computer patch
Manchester Encoding and TV remotes
MSK Modulation
Pseudo Random Shift Register Generators
BAW Resonator Filter model fitting
EF Johnson Low Pass Filter
Elliptic Band-stop Filter
EM sim of a stepped impedance bandpass filter
Learner Linear Phase Filter
Crystal notch filters
Deloach measurements
Ferrite Chip bead modeling
Ten-Tec Jones Adjustable IF Filter
Triplexer for a Harmonic Tuner
W3NQN Harmonic Low Pass Filter
Wideband Inverterr Coupled LC Resonator Filters
A 3-step approach to impedance matching.
One Plus Q Squared and the Resonant pi-Network
Damped oscillation and energy transfer between capacitors
Heath SG-8 Signal Generator and device model for 6C4 triode
ICM Frequency Meter
Muirhead-Wigan Decade Oscillator
RC Phase Shift Oscillator
RC Filtering for full-wave rectifiers
power supply in the Heathkit EK-2B
Full-wave Rectifier Analysis, Otto Schade
Full-wave Rectifier Analysis, Keng Wu
Zener Diode Model for voltage regulation
Lossless flux-coupled transformers
Transformer floating-admittance matrix
Ideal Baluns and Hybrids
Hybrid Transformers , a survey by Sartori
Fitting Auto Transformer S-Parameters
Fitting Transmission Line Transformer S-Parameters
Quadrature coupler , the Cappucci wireline coupler
General Transmission Lines (RLCG)
The QucsStudio component, Lefferson Equations, adding root-Hz dependence to RLCG line model
Indexes (TBD)
References
Author Index
Subject Index
DISCLAIMER: There is no warranty for anything on this personal education web site. It is not to be relied on for professional use. The user assumes all risk of any and all errors which are, most certainly, present.
About the red on black logo for this site: it is an allusion to the six-cavity magnetron developed at Birmingham University in February 1940 by John Randall (1905-1984), Harry Boot (1917-1983), and James Sayers (1912-1993). See the Wikipedia article here