New blog post: Infinite Ladder Network and Its Applications https://niconiconi.neocities.org/tech-notes/infinite-ladder-network-and-its-applications/
Explains the curiosity that the "golden ratio represents the input resistance of an infinite chain of voltage dividers with a pair of 1-ohm resistors". To convince the reader that this circuit is more than nerd-snipping, also shows the derivation of the transmission line impedance without using a single differential equation by cheating via industrial-grade hand-waving. Both are old electronics trivias and should be familiar to veterans in this field... #electronics
electronics
![Let Zin be the input impedance of the original infinite ladder network, now we apply a small modification to this existing network: install a new invented-L section (removing one also works). This creates a new circuit with a finite voltage divider of Zs and Zp, its center tap is connected to the modified infinite ladder network. Now, note that the infinite ladder network is infinite, its impedance does not change in spite of installing or removing a unit.
As a result, its input impedance before and after modification are both Zin equally!
Thus: [equations]
After expansion: [equations]
Solving this quadratic equation yields two roots: [equations]](/proxy/post_attachment/86282/2930317896.webp "Let Zin be the input impedance of the original infinite ladder network, now we apply a small modification to this existing network: install a new invented-L section (removing one also works). This creates a new circuit with a finite voltage divider of Zs and Zp, its center tap is connected to the modified infinite ladder network. Now, note that the infinite ladder network is infinite, its impedance does not change in spite of installing or removing a unit.
As a result, its input impedance before and after modification are both Zin equally!
Thus: [equations]
After expansion: [equations]
Solving this quadratic equation yields two roots: [equations]")
![Assume that every component of this infinite ladder is infinitesimal, and that Zs and Zp are inversely proportional to each other (inductor vs capacitor). By keep using the analysis method called “hand-waving”, we decide that Zs has no contribution to the final result, only the product ZsZp has. This would simplify the impedance equation to:
[equations]
Plugging the impedances of inductors and capacitors into the equation, yields:
sqrt(L/C)
This famous equation is the characteristic impedance of a lossless transmission line, of which its analysis is one of the most celebrated results in the history of electronics engineering.](/proxy/post_attachment/86284/e24dfb0e3b.webp "Assume that every component of this infinite ladder is infinitesimal, and that Zs and Zp are inversely proportional to each other (inductor vs capacitor). By keep using the analysis method called “hand-waving”, we decide that Zs has no contribution to the final result, only the product ZsZp has. This would simplify the impedance equation to:
[equations]
Plugging the impedances of inductors and capacitors into the equation, yields:
sqrt(L/C)
This famous equation is the characteristic impedance of a lossless transmission line, of which its analysis is one of the most celebrated results in the history of electronics engineering.")
Things you find in barns, part 4.
A #klystron #oscillator anyone?
#physics #electronics #radio #uhf #microwave #particleAccelerator #diy
Hi, I'm Sean.
I'm from the oldest incorporated city in so-called #canada, #SaintJohn - home of the #irving empire.
I am an iconoclast - staunchly #antifascist, #antiracist, #anticapitalist, somewhere on the #autism spectrum, and 3 years into punishing #LongCovid. #WearAMask!!!
I've worked the last decade as #HeadOfSound at a beautiful heritage #theatre. Before that I was in #tech for a decade doing #development and #reverseEngineering. I've also worked in #electronics and other #audio fields.
I grew up in a musical family and have played in bands since 13. I'm on around 60 albums, have toured canada and the us, and am part of what is likely the most prolific band in canada: #Slugmilk.
I run a home mixing studio and a small printshop and I have a small "datacentre" which #selfhosts this #mastodon instance.
I'm here on the #fedi to learn from everyone, and to help others learn. I will help anyone with anything I can.
I'd love to meet more like-minded friends - don't be shy!
Things you find in barns, part 7.
This one I really need to look into further. This is the processing unit. Have not found the disk unit, yet. Maybe that part is no more. I believe this to be the Model LF82 #VLS1 from ca. 1973
#computer #retro #electronics #diy #ComputerAutomationInc
My latest blog post: Introducing Touchy Subject
https://mikecoats.com/touchy-subject/
I'm proud to announce Touchy Subject, a Qwiic/STEMMA QT compatible breakout for the AT42QT2120 capacitive touch sensor; development sponsored by PCBWay.
Anyone into #electronics and/or #plumbing?
In my home, I found some fun stuff from the previous owner. One thing was an "Aquaquant" branded thing looking like a simple steel rod that was connected to a water pipe with freaking cable ties. As if that could ever do anything.
A more interesting thing I found was two spools of insulated standard mains wire wrapped around the main pipe then taped. Each spool was connected to the box on one end, and closed (insulated) at the other end.
So all it can do is create an electrical field. There definitely can't be any real current - the entire thing is basically a coil, then a "capacitor" to the water pipe, then the water pipe itself being a basically zero ohms resistor, then another "capacitor" formed of insulation, then the second coil. If you ask me, just estimating, with frequencies below the GHz range nothing interesting whatsoever can happen there, as both capacitances and inductances of those must be tiny.
So, well, what was in the box? Two boards:
- One PCB with a transformer, four diodes; so let's all say it together:
FULL BRIDGE RECTIFIER
and a rather large capacitor. That capacitor is rated for 35V, so let's take that as upper bound for the output voltage. Also, the thing powered a LED behind a resistor for power indication.
- A second board, a stripboard (not PCB!) with some of the traces cut out and of course some blank jumper wires. This board contains a few capacitors and small resistors at the power side (probably interference suppression), then more resistor and capacitor stuff around an 8-pin IC socket. The IC turns out to be a 555.
Now, I didn't plug it into mains, but I tried out the second board with my lab bench power supply in reasonable voltage ranges, and basically whatever I set it to, I get around 700 Hz square wave close to input voltage at the output.
So now I ask:
- What was that thing even good for? 700 Hz low voltage isn't gonna do anything to the water inside the pipe, which actually is a Faraday cage anyway. And all it does is a really weak electrical field anyway (I mean, at most 35V over 10cm distance - I get a stronger electrical field around a button cell) that turns on and off at 700 Hz - there should be basically no magnetic component as at such low frequency the current should be lower than anything I can even measure. AFAIK there's nothing an electrical field that weak at such low frequency can even do to water - even less so behind a freaking metal pipe acting as shield.
- Why not simply have nothing in that box except for the LED? It's not like the 700 Hz circuit even did anything. Only for people like me who open this? But then all those already know it's BS...
- What did the previous owners pay for that esoteric nonsense? I can't find any manufacturer name or label on it. Sure wasn't cheap...
In my home, I found some fun stuff from the previous owner. One thing was an "Aquaquant" branded thing looking like a simple steel rod that was connected to a water pipe with freaking cable ties. As if that could ever do anything.
A more interesting thing I found was two spools of insulated standard mains wire wrapped around the main pipe then taped. Each spool was connected to the box on one end, and closed (insulated) at the other end.
So all it can do is create an electrical field. There definitely can't be any real current - the entire thing is basically a coil, then a "capacitor" to the water pipe, then the water pipe itself being a basically zero ohms resistor, then another "capacitor" formed of insulation, then the second coil. If you ask me, just estimating, with frequencies below the GHz range nothing interesting whatsoever can happen there, as both capacitances and inductances of those must be tiny.
So, well, what was in the box? Two boards:
- One PCB with a transformer, four diodes; so let's all say it together:
FULL BRIDGE RECTIFIER
and a rather large capacitor. That capacitor is rated for 35V, so let's take that as upper bound for the output voltage. Also, the thing powered a LED behind a resistor for power indication.
- A second board, a stripboard (not PCB!) with some of the traces cut out and of course some blank jumper wires. This board contains a few capacitors and small resistors at the power side (probably interference suppression), then more resistor and capacitor stuff around an 8-pin IC socket. The IC turns out to be a 555.
Now, I didn't plug it into mains, but I tried out the second board with my lab bench power supply in reasonable voltage ranges, and basically whatever I set it to, I get around 700 Hz square wave close to input voltage at the output.
So now I ask:
- What was that thing even good for? 700 Hz low voltage isn't gonna do anything to the water inside the pipe, which actually is a Faraday cage anyway. And all it does is a really weak electrical field anyway (I mean, at most 35V over 10cm distance - I get a stronger electrical field around a button cell) that turns on and off at 700 Hz - there should be basically no magnetic component as at such low frequency the current should be lower than anything I can even measure. AFAIK there's nothing an electrical field that weak at such low frequency can even do to water - even less so behind a freaking metal pipe acting as shield.
- Why not simply have nothing in that box except for the LED? It's not like the 700 Hz circuit even did anything. Only for people like me who open this? But then all those already know it's BS...
- What did the previous owners pay for that esoteric nonsense? I can't find any manufacturer name or label on it. Sure wasn't cheap...
if your #electronics are working fine with a reasonable trade in (you get a significant amount of money off an upgrade) or your broken electronics are fixable (they probably are!) and you are considering an upgrade, you don't need an upgrade, you need to change your mindset
Edited 280d ago
My latest blog post: Touchy Subject is Available
https://mikecoats.com/touchy-subject-available/
My Touchy Subject breakout boards for the AT42QT2120 12-key capacitive touch sensor, whose development was sponsored by @PCBWay are now available for purchase at @lectronz.
#Electronics video accounts to follow:
(If an account looks blank, read this: https://fedi.tips/why-does-someones-account-page-look-completely-blank-is-it-really-blank/)
➡️ @kenteh - Electronic gadget teardowns & repairs
➡️ @liz - Colourful electronics, synths, 3D printing
➡️ @mle_online - Building unusual gadgets by altering existing electronic equipment
➡️ @socketwench - 3D printing, electronics, tech, retro computing etc
➡️ @jan_beta - Repairing old computers, esp Amiga
➡️ @morefunmakingit - Repairing old computers, esp ZX Spectrum & C64
🧵 1/3
Edited 300d ago
New video! I'm building a simple 555 timer based logic probe from spare parts I had laying around.
YouTube: https://youtu.be/NhgjBUmnA7k
PeerTube: https://makertube.net/w/cuUPCfYmzMeL8DkFuXgW2a
#LogicProbe #DIYLabEquipment #LogicTester #NE555 #555Timer #Circuit #Schematics #DIY #Homemade #Electronics #Tinkering
New video! Replacing the broken fan in my ZD-915 desoldering station and performing some upgrades.
YouTube: https://youtu.be/26VEOadIn1M
PeerTube: https://makertube.net/w/d5jWSb4xnurBm8Qh6wC9GR
#ZD915 #DesolderingStation #Mods #Repair #LabGear #Electronics #Tinkering
My latest blog post: VanSpoof - Prototype 2 - Echo Firmware
https://mikecoats.com/van-spoof-prototype-2-firmware-1/
In part 1 and part 2 of building my first VanSpoof prototype, I managed to flash the microcontroller on the PCB with a blinky demo. This time round, let's see about sending and receiving some serial data.
#code #eBike #electronics #embedded #firmware #hardware #openSource #reverseEngineering #rust #rustLang #software #stm32 #vanMoof
#Electronics accounts to follow:
REPAIRS
@iFixit - Site all about how to repair consumer & professional electronics
@restartproject - Grassroots initiative to help people fix electronics & electricals
@mees - Videos on how to repair gadgets, home appliances etc
HARDWARE
@adafruit - Manufacturers of open source electronics hardware, based in US
@olimex - Manufacturers of open source hardware, based in Europe
@PCBWay - Custom PCB fabrication service
🧵 1/5
My latest blog post: Low Tech Prototyping
https://mikecoats.com/low-tech-prototyping/
My existing prototypes are too big to fit on the bike, so I turn to one of my favourite low tech prototyping methods; 1:1 scale models in card and fibreboard!
I built a latency meter with an Arduino and a photo transistor to answer one question: Is click-to-photon latency higher on Wayland than on X11?
And the answer is: Yes, actually.
⏱️ 42 ms on X11, compositing off
⏱️ 56 ms on X11, compositing on
⏱️ 64 ms on Wayland
⏱️ 71 ms on Windows 10
Tested with Plasma 6.3.4 and Firefox 137. I will improve my methods and confirm these numbers. See replies for details.
#Arduino #DIY #Electronics #X11 #Wayland #Linux #KDE #Plasma #Latency #Performance #Gaming
Edited 1y ago
I'm looking for a programmer (EPROMS etc). I have a TL866II already, but it requires a Windows software. It runs via Wine on Linux, but not very well.
It would be great if it has at least the features of the TL866, more are preferred. It doesn't have to have a gui, cli is fine. It's also ok to assemble something, doesn't have to be an off the shelf device.
Any ideas or recommendations?
/me Learning how to take notes via SageMath and Jupyter Notebook to keep the algebra manageable. #electronics
#Electronics picks of the day:
➡️ @iFixit - Guides to repairing all kinds of electronics
➡️ @adafruit - Open source hardware manfacturer
➡️ @olimex - Different open source hardware manufacturer
➡️ @librepcb - Free open source electronic design automation suite
➡️ @kicad - Different free open source electronics design automation suite
➡️ @opelex - Project, wiki, podcast on open source electronics
➡️ @GurgleApps - Family videos about fun projects involving electronics, coding, STEM etc
🧵 1/6
Edited 1y ago
My latest blog post: Back 2 Basics - R-2R Ladder DAC
https://mikecoats.com/back-2-basics-r-2r-ladder-dac/
The first in a series of 'back to basics' projects, building real, practical, circuits. This time it's an R-2R Ladder DAC.
#code #electronics #embedded #esp32 #firmware #hardware #microPython #python
My latest blog post: I presented at the 2025 Open Hardware Summit
https://mikecoats.com/presented-at-ohs-2025/
Apologies for the break in blogging, but I've spent the past month preparing for, and then giving, my 'VanSpoof and F**dG3ar' talk at the 2025 Open Hardware Summit.
#electronics #eBike #hardware #OHS2025 #openHardware #openSource #reverseEngineering #vanMoof
My latest blog post: Metronalmost
https://mikecoats.com/metronalmost/
This metronome, by design, will never, ever, tick exactly once per second. This infuriating object is designed to thwart the goals of @hackaday's One Hertz Challenge contest.
#code #electronics #hackaday #microPython #openSource #openHardware
My latest blog post: Reverse Engineering a Broken Night Light - Part 1 - Tear Down
https://mikecoats.com/night-light-part-1/
We bought our first Night Light when our daughter was born; within 3 years, it and its replacement had broken. Let's tear it down, reverse-engineer what's left, and build it back up with some extra 'smart' features.
My latest blog post: Back 2 Basics - Op-Amp Buffer
https://mikecoats.com/back-2-basics-op-amp-buffer/
The second in my series of 'back to basics' real, practical, circuits. Today we're building an Op-Amp Buffer.
My latest blog post: Building the Kilnettle Tape Dispenser
https://mikecoats.com/building-kilnettle/
@stephencoyle presented his Kilnettle Shrine Talking Tape Dispenser as a Lightning Talk at the @oshwassociation 2025 Open Hardware Summit. He was kind enough to send me one to build.