YAY! The Siru.box I ordered just came in. Havent used it yet but its basically a usb controlled and powered power supply. Lets you control the voltage and/or current and even has a very simple API so you can control it programatically. Not sure if/when I will have a use for this but it was cheap enough and cool enough I figured I'd snatch one up.

@Electronics

For anyone who still has devices with old AA, AAA, C, D, or 9V type batteries in it I highly recommend you move over to the USB chargable Li-ion type of the same format.

Most of those devices dont work with traditional rechargable batteries like NiMH because the voltage is a bit lower. Even if they do work they tend to last only a short period of time because as they discharge the voltage drops even further. So your device will often die even with 70% of charge still in those batteries.

With the newer USB rechargeable Li-ion type batteries of the same form factor, however, you have a drop-in replacement that doesnt have those issues. They basically are a LI-ion battery with a built in charger but more importantly with a DC-Dc converter to keep the voltage fixed at the desired voltage (1.5V or 9V) for the entire life of the battery. So they work in any device that they can fit in and lasts a long time as they deliver 100% of their power before cutting out (at which point it drops from 1.5V directly to about 0V).

The only downside is if your device reports a battery percentage then it will report 100% battery right up until it hits 0.

Anyway I replaced all my devices with batteries like this and they last longer than regular batteries in some cases (especially with 9V)... so I am sold!

Found this in my notes from a while back. Shows how to calculate the values for a balun to match a transmission line to an antenna.

@math

Man I wish the American economy still had small stores like this... Radioshack put them all out of business then stopped selling it when places like digikey put THEM out of business.. now you can only order from a catalog and its just not as satisfying.

ledpixelart.com/shenzhen/


@Science

@Science

So here is a question some of my EE and radio friends disagree on... Is a purely resistive matched load, like a 50 ohm dummy load, considered "resonant". In the strictest sense of the word is that a valid term here?

While it would seem odd I'm leaning towards yes, and would be the simplest example of resonance.

For this weeks I am going to do a groups addition.

  • @Electronics - An Electronics Group
  • @theamazingweb - A group about interesting and novel things on the internet.
  • @vim - A group for everything VIM
  • @funny - A group for humour and memes
  • @mnmlsm - A group devoted to discussing unix and related topics
  • @calligraphy - A group devoted to sharing and discussing calligraphy & handwriting
  • @FreeSoftware - A group for discussing Free and Open-source software
  • @math - Everything math!
  • @dogs - A group for sharing pictures of dogs, for any reason.
  • @Science - A group to discuss Science topics.
  • @photography - A group for sharing or discussing photograph.

So its been about a month since the QOTO Moderated Groups Server came online at groups.qoto.org. It adds group capability to the fediverse with an owner capable of moderating membership in the group unlike previous group servers which were completely unmoderated and open.

We have had some amazing groups form and overall the server seems to be the most popular on the fediverse, I’m seeing more activity than the open-group servers which is great!

As such I wanted to share a list of a few groups I know of so far in case anyone is looking for a group to follow. Just follow the group as you would a user and you will be in the group and receive group posts in your timeline!

@Electronics

I wanted to share a write up I did not to long ago explaining circuit duals with a specific focus on magnetic circuits. They behave the same as an electric circuit in the sense that anything you can do with an electric circuit there is an equivalent way to do it with a magnetic circuit. A magnetic circuit is a circuit that uses the magnetic fields propagating through “wires” rather than electric fields. It’s a very cool idea and worth a read, though all the usual electric concepts are flipped, for example instead of talking about electromotive force (EMF/voltage) you would use magnetomotive force instead (MMF) as filling the same function as voltage in an electric circuit.

Let me know what you think, this tutorial was a week long effort to write.

jeffreyfreeman.me/an-indepth-l

@General

@Electronics

Finished most of the prototype board. Never have I been so excited to solder something, specifically the shield. After several years of hard work putting that shield on was a trophy! Its something that has collected dust for periods too and this is the second version I went full cycle on.

For those wondering this is the RF analogy board for an advanced highly percise SWR meter with Network-analyzer like capabilities built into an shield. It measures a radio signals forward and reverse properties and compares them including complex impedance, complex reflection coefficient, SWR and much more. with two of them and a zigbee you can even operate one at your transmitter and the other at the antenna end and get both readouts in the shack. Cool stuff!

The yellow shielded wire wasnt working so I added a very tiny red wire instead. The final product wont need this and it may introduce some issues with the prototyping, lets hope not.

If you want to see more pictures of the project, including the GUI demo running or the earlier v1 version just check out the hashtag.

Man ive been at this over 2 hours now and havent even covered a square inch yet. It messes with your head how damn small these 0402 components are.

@Electronics

@Electronics

Man soldering 0402 components is brutal. I wouldnt wish this on my worst enemy... but progress is being made!

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