The Great Circuit Challenge!

AnalogKid said:

Corrected: Nobody's ever happy.

Better: Nobody ever is happy.

Now I'm happy.

ak

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Better,
"My ambiguity has generated a happiness deficit."

The point of the thread was to be a fun game of whimsical circuit design challenges. Not a contest of arbitrary grammar and linguistics nit picking.

Got a circuit challenge, a solution to one or a query about one that's been given, then post it.

Got a nitpick about anything else, that serves no relevance to the game, go start your own thread about it.

tcmtech said:

a contest of arbitrary grammar and linguistics nit picking.

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Sounds like fun to me.

ak

AnalogKid said:

Sounds like fun to me.

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Then go start your own thread on the subject and continue on with your game from there being its unwanted and unwarranted here and rather constitutes deliberate trolling by my views.

Consider this my only request of you take it someplace else, or stop doing it, and participate in the thread for what it was made for if you wish to stay here.

Duncan Amps has various vacuum tube spice models.

As long as someone doesn't want to create a phanastron oscillator circuit, we will be in good shape.

JoeJester said:

a phanastron oscillator circuit

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Damn, that was going to be my next challenge too. Make a hexode or heptode vacuum tube based oscillator or frequency shifting converter of any sort.

Here's a tube found in some divider circuits ..... in some of the equipment I worked on.

Challenge 4. Voltage regulating half bridge rectifier using SCR's.

Make a Constant Voltage output linear power supply/battery charger circuit that uses a center tapped transformer with two SCR's and whatever other circuitry you need to produce a reasonably stable DC voltage over a 10:1 or greater current draw bandwidth from a CT transformer that has at least a ~1.4:1 peak center tap voltage over the averaged DC output. IE, ~12 VDC output from a 24+ VAC center tapped (12 - 0 - 12) or higher source.

No parts limit.

tcmtech said:

Nobodies ever happy. I type lengthy detailed posts and people complain they are too long and then I cut things back and now they're too short.

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Hey tcmtech - Please rest assured you're not alone! -- But then considering what became of Goldilocks...

Very best regards
HP

tcmtech said:

Challenge 4. Voltage regulating half bridge rectifier using SCR's.

Make a Constant Voltage output linear power supply/battery charger circuit that uses a center tapped transformer with two SCR's and whatever other circuitry you need to produce a reasonably stable DC voltage over a 10:1 or greater current draw bandwidth from a CT transformer that has at least a ~1.4:1 peak center tap voltage over the averaged DC output. IE, ~12 VDC output from a 24+ VAC center tapped (12 - 0 - 12) or higher source.

No parts limit.

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Bob Carver has you beat by about 30 years... the power supplies on his amplifiers used triacs and SCRs to regulate the rail supplies for the amp boards.

unclejed613 said:

Bob Carver has you beat by about 30 years... the power supplies on his amplifiers used triacs and SCRs to regulate the rail supplies for the amp boards.

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I know everything I have asked for has been created a multitude of times over. I have my own versions of them as is.

Its just supposed to be a game to challenge others to dig into the concepts and come up with their own solutions.

It was intended to be a basic technical design logic puzzle game to challenge peoples knowledge bases and critical logic thinking skills, that's all. However what it's revealing so far is rather quite disappointing for multiple reasons on multiple levels.

from what i've seen following trade magazines for the last 30 years or so, is a lot of people are being taught, not so much the "nuts and volts" of electronics, but more of a "systemic" approach. this means you don't see anybody actually designing an oscillator anymore, when they can code a PIC to do the same thing. where there actually is any experimentation with basic analog circuit elements, they are often bizarre renditions of previous technology that are more of a curiosity than they are useful (and they become a passing fad as well), like "current conveyors" (which are simply, a cascade of current mirrors on a chip). how many people can actually sit down and design an audio amplifier or an op amp circuit (the op amp itself, not only circuits that use them) anymore? how many people can tell the difference between a Colpitts and a Hartley oscillator? what's the difference in switching speed between a transistor that goes in and out of saturation and one that doesn't (and why is one faster than the other)? a lot of the basics aren't getting taught anymore. some of it is because you can dump a bunch of stuff onto a piece of silicon and not have to worry about how it works, and some of it is because they're trying to cram a lot of information into a short time frame, and leave the rest for people that want to specialize (why learn about RF circuits when you are designing digital hardware?)(actually that was a loaded question, and intentionally so).

At the moment, I'm hard pressed to think of any analog device that can't be replaced with some manner of digital gizmo, other than an amplifier...

Don't see how you'd ever make a bit (0 or 1) any more robust...

tcmtech said:

Damn, that was going to be my next challenge too. Make a hexode or heptode vacuum tube based oscillator or frequency shifting converter of any sort.

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i guess that's challenge #3?

a phantastron can be done with a pentode that has all 3 grids available...

cowboybob said:

At the moment, I'm hard pressed to think of any analog device that can't be replaced with some manner of digital gizmo, other than an amplifier...

Don't see how you'd ever make a bit (0 or 1) any more robust...

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That's the whole point of the challenges. To challenge people's working understanding of how the laws of physics work. No matter how much digital processing power you throw at something there still has to be analog interface between it and whatever it controls.

I've wasted too much time in my life as is watching the masters of the digital realm get their butts handed to them by a analog side noise issue throwing a bunch of unwanted 1's and 0's in to their code because they figured that whatever was making their systems malfunction had to be code based.

As for a bit being robust I greatly disagree simply due to my experience of seeing just how fragile digital systems are when it comes to any degree of external interference or influences. How much of our electronic world is now utterly unserviceable because of an unneeded digital something or other having been put in it only to have it screw up on the code level?

unclejed613 said:

from what i've seen following trade magazines for the last 30 years or so, is a lot of people are being taught, not so much the "nuts and volts" of electronics, but more of a "systemic" approach. this means you don't see anybody actually designing an oscillator anymore, when they can code a PIC to do the same thing. where there actually is any experimentation with basic analog circuit elements, they are often bizarre renditions of previous technology that are more of a curiosity than they are useful (and they become a passing fad as well), like "current conveyors" (which are simply, a cascade of current mirrors on a chip). how many people can actually sit down and design an audio amplifier or an op amp circuit (the op amp itself, not only circuits that use them) anymore? how many people can tell the difference between a Colpitts and a Hartley oscillator? what's the difference in switching speed between a transistor that goes in and out of saturation and one that doesn't (and why is one faster than the other)? a lot of the basics aren't getting taught anymore. some of it is because you can dump a bunch of stuff onto a piece of silicon and not have to worry about how it works, and some of it is because they're trying to cram a lot of information into a short time frame, and leave the rest for people that want to specialize (why learn about RF circuits when you are designing digital hardware?)(actually that was a loaded question, and intentionally so).

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That's the part I dont get. How do you properly design a digital code to control analog systems without knowing how analog actually works?

I've fought that battle for years with doing even basic PLC programing work. If you don't know what the analog systems are doing by the laws of physics that govern them there's no way to make a good program or digital system work to emulate it accurately.

tcmtech said:

Challenge 1. Blinking LEDs the old fasioned way.


555 timer IC or some sort of astable oscillator circuit.
Vacuum tube or tubes.
LED's.

Intended End Function.

Make two, or more, LED's blink alternately/successively at 1 - 2 second intervals using a 555 or similar astable oscillator device/circuit (discrete/IC, solid state or vacuum tube based) and a vacuum tube or several of some kind.

No other parts or design limit.

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1.5s duration toggle repeating.
3 parts + 2 LEDs + 2R's
https://tinyurl.com/y8x4pdx5

that's the point i was making with my "why learn RF" comment. sooner or later those 1s and 0s have to get from point a to point b, and there's no "purely digital" way to do it. even within a CPU chip, there are propagation delays, issues with power dissipation, signal crosstalk, etc... that have to be carefully balanced. there are even whole logic families that use purely analog circuits (i'm thinking of ECL, which uses various configurations of analog diff amps running in class A mode to accomplish logic functions). that's why such brain teasers as TCMtech has posted have value. a little bit of "out of the box" (or more accurately "out of the chip") thinking is always good.

Don't see how you'd ever make a bit (0 or 1) any more robust...

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when that 0 or 1 has to travel through a cable, or through the "ether", how do you know it's a 0, 1, or noise? there's really no such thing as a purely digital system. you have to move bits and bytes around through an analog world. the "hype" about HDMI is that "it's a digital media transport". if it were purely digital, there wouldn't be any limits on HDMI cable length, and the quality control of HDMI cable manufacturing wouldn't be necessary. the facts about HDMI are that yes, it's a digital transport for data, but to get those bits from the disk player to the TV requires the analog characteristics of the cable to be carefully controlled during the fabrication process, or the data won't get to it's destination in any usable form.

Tony Stewart said:

1.5s duration toggle repeating.
3 parts + 2 LEDs + 2R's

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That's the easy parts. Where's the vacuum tube!

We all know that such a simple circuit does not need one but that's what my challenges are about. Adding a nonconventional part or other requirement into a otherwise simple circuit because it would take a bit of out of the ordinary thought process to get it to work.

(Mostly I just want a vacuum tube based conversation piece with blinking LED's to put on my entertainment center. )

unclejed613 said:

when that 0 or 1 has to travel through a cable, or through the "ether", how do you know it's a 0, 1, or noise? there's really no such thing as a purely digital system. you have to move bits and bytes around through an analog world. the "hype" about HDMI is that "it's a digital media transport". if it were purely digital, there wouldn't be any limits on HDMI cable length, and the quality control of HDMI cable manufacturing wouldn't be necessary. the facts about HDMI are that yes, it's a digital transport for data, but to get those bits from the disk player to the TV requires the analog characteristics of the cable to be carefully controlled during the fabrication process, or the data won't get to it's destination in any usable form.

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I ran into that problem when I was in oil field a lot. The company I worked for used ethernet based interconnections for everything between the data van control centers and everything else and our longest ethernet cords were 200 feet. Problem was that for a few of our higher data bandwidth pieces of equipment they worked on a 200 foot interconnect lineset just fine in a singular 1 - 1 connection but if the site got set up wrong even adding even a 25 foot extension to its 200 foot cordset made that whole machine drop out of the network and refuse to talk to everything else yet still pass a connection ping test from every point in the system every time.

The only cheat was to daisy chain that unit through a midpoint machines systems 1 - 1 - 1 and have it work as a passthrough router of sorts assuming it plus the remote machines combined data rates did not then over load its connection bandwidth limits to the main data van systems, which most did, given the type of ruggedized industrial ethernet cord sets we used had terrible data rate capacity numbers. You could pull a small car with one but you couldn't expect much over 50 - 100K data rates at 200 feet and no amount of software would change that limit.

Analog reality choked the life out of digital function every time and very few understood why. I didn't and I chased that ghost for the better part of day before I finally got a explanation for it. Cord bandwidth Vs machine connection bandwidth requirements at a distance didn't add up.