The Great Circuit Challenge!

As some of you saw a new member posted a odd little challenge to design as specific circuit just for the fun of it so I figured I would spin it off into a more diverse competitions if I can by expanding on the idea that we all can play at will with no real endgame in mind.
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1. Put a number and title on your challenge so that others know whos replying to what with whatever solution or improvement or critique on somelese design they may have.

2. Pick 2 - 10 common-ish electronics/electrical/electrically related component items from any field and or historical time frame to make something useful or just whimsical that implements all of them.

3. Describe the goal. Either its an - Intended End Function - challenge where you want them to do a specific final action or its a - Open Design - challenge where so long as all the items serve a purpose in the circuit they count.

4. Enter and solve as many as you wish however ways you wish being there is no single solution so 'Rube Goldburging' a concept is allowed too.

You can either physically build one for proof of concept to simply post a circuit with an optional simulation of it. Just state your intent with your design be it to be most/least simple,efficient, odd, or whatever. Simply explaining yourself on both your proposed challenge and or your solutions to challenges is all that matters.

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.

tcmtech said:

Challenge 1. Blinking LEDs the old fasioned way.

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Notice the 555 timer in this design is used slightly different than most 555 designs. It is a less published valid approach to using a 555 to ensure a 50/50 duty cycle.

Where's the vacuum tube? It's gotta have a vacuum tube (or several ) in play to count! (hence the challenge!)

And yes, I too do prefer to use that version of the 555 timer circuit when possible.

It's been around for long time. So much so that I first saw it back in the early 1990's in car audio work I saw it used many times as the main driver for the DC - DC power supply end of many amplifiers.

Some ran it directly as an unregulated DC - DC converter and other added a JK flip flop and a pair (or four, maybe?) of comparators to the output and then fed back the stepped up voltage to the Control pin and comparators to make it all work as a crude PWM voltage regulated push pull type DC - DC converter circuit. ( I forget how exactly now but it did work rather well with minimal parts and for really cheap.)

tcmtech said:

(discrete solid state or vacuum tube based)

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... I saw this and thought OR ... I didn't quite understand the ...

tcmtech said:

and a vacuum tube or several of some kind

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... it might be hard to find someone that can design using vacuum tubes these days.
Fortunately my mentor when I worked at National Semiconductor was quite the tube guru.

Beau Schwabe said:

... it might be hard to find someone that can design using vacuum tubes these days.

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Exactly the point! I don't hand out feel-good participation trophies for doing things part way because it's easier than doing them the right way which is way harder.

Hence the words ' GREAT and CHALLENGE' in the title. The whole game is to challenge people to think outside their normal range and scope of skill sets and knowledge.

FYI, I rewrote the first challenge criteria to better clarify what needs to be in play.

Can I just use the filament as a jumper?

Sure, why run the marathon when you can take the bus to the finish line, right?

It's your circuit so..... your call.

it took a while to find a tube model that didn't confuse LTSpice when the circuit has recursive feedback like a multi does. it think most of those models are optimized for audio/RF. i found a simpler model that works for DC circuits with recursive feedback. once i got rid of the "time step too small" errors, the circuit worked like a champ...

tcmtech said:

No other parts

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It's gonna be tough without some passives and a power supply .

alec_t said:

It's gonna be tough without some passives and a power supply .

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Where did I specify that?

You TL;DR'ed on a 6 word sentence?

https://en.wikipedia.org/wiki/Wikipedia:Too_long;_didn't_read

he took "no other parts or design limit" to mean "no (other parts) or (design limit)" rather than "no (other parts or design) limit".

How? Its six words with no arbitrary punctuation or implied double meanings or anything?

Is it a language barrier issue I am not familiar with?

tcmtech said:

How? Its six words with no arbitrary punctuation or implied double meanings or anything?

Is it a language barrier issue I am not familiar with?

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Sometimes "too concise" becomes "too vague". I am confused with your language as well. I now understand your rules to be...
We must use ALL parts listed and ANY ADDITIONAL parts we want, correct?

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.

Anyway, Yes. If say, 3 items like a Op-Amp (of undefined design) plus a neon bulb, and a SCR are listed as the key items then at least one of each (plus whatever additional parts to make any of them work in their as to be used function) are to be used.. Anything extra is fine, in fact the more creative use of extra parts the better!

Power supplies, power sources and whatnot plus any other ancillary parts of non
specced value are just assumed to be in play as you need to use them. If a 9 volt battery will work, but you want to use a Ford model A engine and generator set instead then put it in your design!

There's really no additional parts count limit so if you want to make a 1 megohm resistor using 100,000 10 ohm units in series then that's what you can do.

The key is to use the few listed specced items as part of the whole circuit design to do a end function regardless of what extra non listed parts of your choosing you care to throw in the mix.

The game isnt to make a specific circuit but to make ANY circuit that uses the key listed components (plus whatever else your imagination come sup with) to do the intended end function. The only caveat on the required and extra parts of your choosing is that if anyone of them was removed the circuit would not work as it is intended to.

So, yes if someone wants to use a vacuum tube heater element as a circuit pass through then it does count, even if its just being lazy to use it that way. (and you can call them out fo for doing so too. )

Guys, I think you missed the "". I was pulling your leg, tcm .

Challenge 2. Multi stage step sequencer using only relays with simple discrete components.

Make 3 or more devices of your choosing activate in 1 or more second stepped sequence then reset after last stage and start over using relays as the primary active devices.

No active IC based devices (Timers, Op-Amps, Comparators, Digital or such) or multi junction discretes (transistors and like switching devices) to be used.

Resistors, capacitors, single PN junction discretes, mechanical, etc plus power source of your choosing only.

alec_t said:

Guys, I think you missed the "". I was pulling your leg, tcm .

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The downfalls of attempting humor, or assuming humour was in play, when there was none due to the ambiguity of text communication.

tcmtech said:

Nobodies ever happy.

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Corrected: Nobody's ever happy.

Better: Nobody ever is happy.

Now I'm happy.

ak

Abraham and Bloch were ahead of Eccles and Jordan by one year.

Here's one from 1942. Add LEDs and shake well.

ak