I had an epiphany today: Mastodon is my makerspace. I haven't been able to find a makerspace in this area since we moved here in '22, and that's been bugging me. But I scroll through Mastodon and see people's printing, woodworking, electronics, and welding projects, and I admire them, and sometimes I ask questions and learn new techniques. And when I post my own, people do the same.
That's a makerspace.
@3dprinting #MakerSpace #woodworking #fpga #electronics #DIY #3DPrinting #welding
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
I made a #diy #electronics standalone #cryptography #cybersecurity device the ParanoiaBox. It is an experiment with a minimal attack surface as it is a #microcontroller, keyboard, television, with no operating system intended for #encryption and decryption of files between an insecure air-gapped computer and the internet. It uses AES256 and ECDH EC25519 public-key encryption to enable #secret #communications. Files are encrypted into text so they may be easily E-mailed or posted on forums.
This is an #amateurradio #qrp T-match antenna matching unit made with two PCBs. It includes a resistive bridge for testing the match while presenting a low SWR. The inductor is a tapped PCB spiral inductor and the capacitors are two circuit boards that slide past each other. You add some switches, coax connectors, resistors, and diodes, for a total of about $4.00 in parts. Make it a project at your club!
![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.")
