Alan Wolke teaches electronics on his W2AEW channel with a sketch, a breadboard and a bench full of instruments. This repository rebuilds those circuits in LTspice, so you can run one yourself, change a value and watch what it does.
LTspice can simulate the power supplies, meters, oscilloscopes, and spectrum displays that Alan uses. The notes in each chapter connect the simulated results to his measurements and explain where the model differs from his hardware. This does not replace watching him explain the material; it simply lets you construct the same circuit even if you don't have the equipment.
If you haven't subscribed to Alan's channel yet, you should. More than 230,000 people already have, and with over 400 videos, it's easy to see why. He explains things clearly, takes his time, and knows his stuff. He makes you appreciate electronics, ham radio, and how to get the most out of test and diagnostic gear.
Video 167 is a fair sample of what a chapter holds. Alan builds a diode ring mixer on the bench and shows why it hands you the sum and difference of its two inputs. The same ring is drawn here in LTspice, driven by his 7 MHz local oscillator and 10 MHz RF.
Four Schottky diodes in a ring between two center-tapped transformers, with the IF taken from the RF winding's center tap. Every part on the drawing is one you could wire up.
An FFT of that circuit. The local oscillator stands at 7 MHz and the RF at 10 MHz, while the IF output carries their 3 MHz difference and 17 MHz sum, which is what a mixer is for. Its chapter notes identify each marked peak and separate Alan's values from the modeling assumptions.
- Install LTspice. It is free, and every schematic here is a plain
.ascfile. - Download or clone the repository and leave the folders where they are. Some schematics reach into the shared LTspice folder by relative path, so rearranging things will break them.
- Pick a video from the table at the bottom, then read that folder's
CIRCUIT_NOTES.mdalongside it. - Open a circuit's
.ascand press Run. If the waveform window comes up autoscaled, press Ctrl+Space to load the view saved in the.pltfile beside the schematic; stepped runs nearly always need this. Chapters that build an FFT say what else to do.
You only need LTspice if you want to run something. The notes and the captured plots read perfectly well on their own.
Every video gets a numbered folder, and the CIRCUIT_NOTES.md inside it is the guide. It links to the video, says what the circuit is for, walks through what the simulation produces, and flags the assumptions worth knowing about before you compare any of it with Alan's bench. The video index PDF that Alan links from his channel is here as well; Dino (KL0S) compiled it.
Numbered subfolders such as 01 - Diode ring mixer/ hold the circuits in the order they appear in the video. Each circuit has at least one LTspice .asc schematic, PNG images captured from LTspice for the schematic and relevant plots, and a time-coded video link that takes you to the point where Alan introduces it. A circuit may have more than one .asc file when separate simulation views are useful, plus .plt plot settings and the .log holding its measured results. Waveform files are not stored here, so running a circuit writes its own .raw. The symbols and third-party models the schematics need are collected under LTspice/. For example, video 167's diode-ring mixer links to its demonstration from 0:00 and contains transient and spectrum examples. An optional alternative transformer model sits in its own clearly named subfolder.
| Chapter component | Video 167 example | Purpose |
|---|---|---|
| Chapter guide | CIRCUIT_NOTES.md | Explains the video, circuit operation, plots, results, and model assumptions. |
| Video and source notes | video shortcut and Alan's handwritten PDF | Links to Alan's demonstration and provides his original notes when available. |
| Numbered circuit folder | 01 - Diode ring mixer/ | Groups the files for the first circuit shown in the video. |
| Editable LTspice schematics | transient .asc and spectrum .asc | Run the circuit and inspect the time-domain or FFT setup. |
| LTspice PNG captures | schematic, transient, and FFT | Show the circuit and representative results without opening LTspice. |
| Saved plot settings | conversion example .plt | Restores the selected traces and display settings for a simulation. |
| Circuit introduction link | time-coded .url (watch from 0:00) | Jumps to the point where Alan introduces this circuit. |
| Optional variant | Alternative T1-6T-X65+ model/ | Keeps an illustrative transformer variation separate from the main circuit. |
Video 185 shows how a chapter with several circuits is arranged: fixed base bias, collector feedback bias, and voltage divider bias. Its chapter notes link to the point where Alan introduces each circuit.
The PNGs are there so you can see a result without opening anything, and the .asc files are there so you can change a value and watch it move. What comes back depends on the device models and the test conditions, so read the notes before taking a simulated number as Alan's.
ltspice-keyboard-shortcuts.pdf is Analog Devices' four-page quick-reference card for LTspice 26. Everything here is drawn and run in that editor, so it is worth keeping open: shortcuts for the schematic and waveform windows, the SPICE directives and netlist line types, the simulation commands, and the .options parameters.
Two entries on it are worth reading before typing any component value. LTspice parses suffixes case insensitively, so M means milli and mega must be written MEG, and a bare F means femto rather than farad. Both mistakes simulate without complaint and are wrong by orders of magnitude. A unit may follow the prefix and is ignored, so 10nF is safe; only a bare F or M straight after the number is a trap.
The card is copyright Analog Devices.
There are almost certainly mistakes in here.
I put these circuits together by watching Alan's videos and working from his notes, so sometimes I will simply have missed his point. A schematic can match his drawing and still be a poor illustration of what he is demonstrating. I can misread a value off the bench. A chapter can explain something clearly and confidently and still have it wrong. I am not an LTspice expert either, and a simulation that runs and draws a believable-looking plot is no proof that I have set the circuit up the way Alan sets up his.
So if the video and this repository ever disagree, trust Alan. The mistake will be mine.
I would genuinely like to hear about it when that happens. If something looks wrong, or you know a better way to model it, or an explanation just does not make sense, open an issue and say so. If you would rather fix it yourself, even better: clone the repository, make the change, and send a pull request. I will read every one. Schematics, chapter notes, plots, model assumptions, anything at all.
CONTRIBUTING.md has the practical details, including the one piece of local setup a clone needs before you commit a simulation log.