Make a very simple test for me

[_q12x_]

Im asking this question to everyone but in particular to my friend here mister @marconi .
I am a professional artist but I am not an electronist like you guys here. That doesnt mean I dont know anything. I know something but I can't raise to some of your standards and knowledge. I'm happy (sometimes fun) to learn something new here and there.
- Recently, it was suggested to me to buy a frequency counter, because I got into some crystal oscillators I have in my stock and they have no markings anymore and the reason is a bit too long story. I already buy a cheap one from ebay, exactly this yellow version (not the red one)

but it is on the road. I have about 2-3 months (usually) to wait, until it arrives.
I also have a dinky DSO138 osciloscope that is trembling of Parkinson all the time. So you can imagine, I can't put my 100% trust in it all the time.

So, my first circuit for testing a crystal oscillator I find is this:
"Oscillator Circuit of The First Quartz Wrist Watch"

I had high hopes for this circuit. I used 10k for both Rc(c=collector) and 1k for both Re(e=emitor). And I used BC548 for both Tr.I used a known value of a Quartz of 20MHz. And I used 2V (VB=Voltage Battery). But the oscilloscope just showed me some very weird and random readings that I can not even put head to tail. I build this circuit on my breadboard, and that may had influence the results.

---So this circuit didn't work for me---. But I bet my as it must be a good one and I blame my DSO138 for being crappy.
And also not having (yet) a frequency counter.
- In short, this is more a curiosity for me. I hope it is for you as well.
- My request for you is to help me with the following:
- Because you are a better electronist, you must have better tools than I have. So, using your normal oscilloscope and your normal frequency counter, (I say normal, comparative to my ebay measuring tools), please make this very quick and simple circuit and measure it for me. And confirm to me with some images or a short video, that everything is working as I imagine and hope. It must be. The idea is to measure 20MHz on the "out" pin in respect to the ground (if you used the same values as I used). That's it. Also, feel free to change the resistors or the transistors. It must be GPT (general purpose transistors), but the resistors I used I just guessed their values. I didnt had the values from the page with the circuit. So I had to invent something. And those values are my best guess.
Thank you and hope to hear good news from you.

 

[_q12x_]

I and you do not know whether the variation in division result is due to variation of the input from your PWM circuit or in your 555 divider circuit or both.

That is true. We cant know for certain. BUT...my very best guess, is this signal, created by the PWM is like a picture of 800x600. When you look at it from afar, from distance, it looks detailed and good to watch, and no problems, right? Now, when I add a magnifying glass, which is our "splitter"/ fv divider here, that is magnifying by 100 times in my practical case (1/100), NOW we can see the bloody pixels in that image. Right? So again, my best guess, the source of the signal is good to a point or to a magnification. After that is crapping itself down. But...
- Doesnt matter from where is the source !!! We must add a "silencer" / "a filter" that will let flow only the important thing.
Again, im not the math guy here so you'll have to understand this aspect about me. Im better at visual representation more than anything. Im trained on it all my life actually.
My idea that is not finished yet, but I will expose it as unfinished as it is, is the folowing: we dont go in the range of 10Hz to 6Hz where the fluctuations are the worst. We go a bit higher. Let's say to 20Hz just to be sure. Right? Now, from this "sure" position, we can start trim and cut and filter what we need and send out only a constant flow of impulses at 20Hz and the rest of fluctuations trim off or avoided somehow. And this is where my idea stops.
Actually it is in my plan to try a very simple approach, like we deal with 240V filtering, after all this is also a fluctuating current, right? and I will add a filtering capacitor in the output of this fluctuating crapping itself signal. It is in plan, I have to try it. This is the simplest idea I could think.

 

[_q12x_]

Hmmm. I managed to clean the output of the PWM and get a VERY stable output reading from the fv counter for the 1/100 level.
But I could not make it to 1/1000. I tried many ways.
First I hooked up the 1/100 board I just built to the breadboard with a 1/10. And it kept showing me the same output as the input. Very-Very strange. Logically you would expect another division. But noooo.
Then I said, blaimy, I leave only the breadboard circuit and tried to bring it down to 1/1000 as a single circuit. It didnt work because the fv counter can't count 0.x x x fv. It just stops at 0 and thats it. It actually jumps from 8 to 0. The most I could get it down was 2Hz, and I thought on a logical RC arangement of values to try for the 1/1000, that it wasnt working for the fv I had to test with, but MAYBE, it will work with the crystal.
Then I hooked up the crystal and ... nothing. I put it at 1/100 and it should have giving me something around 200kHz, what the maximum of this device could see, I was hunting for some variations at the border, but nothing. Then I tried a 14MHz crystal with also 1/100 model and it should had shown something. And it didnt. Then I tried my theoretical RC values for 1/1000 and nothing worked either. Also put both crystals and again, nothing. It was staying on 0 Hz all the time.
Then I measured the output of the circuit, oh, I used your circuit mister @marconi with 1 transistor, and it give me 4V, so it was an output from that, no doubt.
I made so many permutations today, I am tired.
Funny story: I unhooked everything from the fv splitter circuit but I touched the input wire with my fingers. And the fv counter showed a clear 50Hz - hahahaha, I dont even have to plug it on the mains, I am vibrating at this fv anyway. Now that Im thinking it should have been 5Hz since it supposed to be splitting. I noticed sometimes, in certain conditions, the output is equal with the input of the fv splitter.
Then, I had another bright idea, to check the maximum fv of the 555 ! And I checked the internet, and it says "500-kHz to 2-MHz ", ok, then I looked in its datasheet and it says:

and I didnt find nowere the fv of the 555 mentioned in its datasheet. This values here, the 100ns are the only ones I could find and I thought I can convert that into Hz, and I did, and guess what, 100ns = 10000000Hz = 10Mhz . I beat the internet with this finding, but still not good enough for my 20MHz crystal. So.... Im screwed with this experiment. Its a test anyway. But I am not happy that logic splitting didnt work. It should had. I was counting on it. Eh well, life lesson, never expect anything.

 

[marconi]

Deleted post and some extra words

 

[_q12x_]

How is your progress, signore @marconi ?

 

[_q12x_]

And, we are turning back to some of my previous ideas.
My greatest suspicion is that 555 circuit could not do its job do to a much greater fv in its input than he is designed to support and see.
So....my previous idea that someone here laughed at, was to make a discrete fv splitter. We need it for a couple of times, not the entire 1/1000 range.
- So I ask again, give me your best discrete circuit that is capable reliable to split a very high fv !
My plan is simple: I will split it a couple of time using discrete fv splitter circuits, and after is down under 10MHz as the datasheet of the 555 mentioned (or 2MHz as the internet says) after that, I will input my 555 fv splitter circuit. Simple. And this is a good plan. I will do the work anyway.

 

[marconi]

How is your progress, signore @marconi ?

Good morning. I had a day off yesterday. But I was thinking about whether:

a. to use an opamp or transistor to amplify the signal;

b. to pause on (a) and make a crystal oscillator instead using a 74HC04 as Lucien did from which one can produce a square wave very easily 5V-0V to drive the 74 series divider. This approach keeps things very simple whereas (a) would require more tinkering* around. Alas I do not have as much patience as you do so prefer to keep things simple these days. I have posted you some 74LS04s and 74LS00s so it may be possible to use these instead of the HC04s. I will have a rummage now in my shed for some.

*tinker around with - https://idioms.thefreedictionary.com/tinker+around+with

 

[pc1966]

The simplest divider I can think of would need at least 3 transistors (without resorting to odd devices like the unijunction transistor), two for the state memory (i.e. flip-flop) and a 3rd to try and steer it to change state on each edge. Others seem to have the same idea as here is an example of a T-flop (scroll down the page):

Flip-Flops Using Discrete Transistors

Flip-Flops Using Discrete Transistors: Hello everyone, Now we are living in the world of digital. But what is a digital ? Is is far away from analog ? I saw many people, which believes that the digital electronics is different from analog electronics and the analog is a waste one. So her…

www.instructables.com

But, as Lucian pointed out, they end up with RC time constants that limit the useful frequency range. The example on the link above would not operate anywhere close to 20MHz due to the high-ish R and stray capacitance, device capacitance, etc.

If you get a 74HC4060 then its input gate can be an oscillator or simply an amplifier for squaring-up the output of a transistor oscillator, and then you get the dividers all working as part of the deal.

 

[marconi]

q12x Here is 74LS00 crystal oscillator which you can make when the box of ics arrives. Now you have three circuits you can make to test your crystals with.

 

[_q12x_]

Thank you signore @marconi , very good progress so far. Don't forget to actually post the circuit for this last experiment with the 74LS00 in the video. Drawing on paper is the fastest way.
To mister @pc1966 , yes I found the exact same page. Its good that you mentioned that RC limiting problem, not reaching 20MHz. Then what would a circuit be not limited? Can you guys think on creating and also testing (having all that nice osciloscopes) such a circuit for me?
I was thinking, how the light measuring devices are functioning?
What circuits they have inside that actually measure such great fv values? Yes, visible light
Electromagnetic_spectrum

Maybe we can use something that they use, you know? That's my idea. A special sensor or a special circuit.
- The conclusion so far, is that I can Not build a discrete fv divider ? That sucks...
- To be totally sincere, I didn't put quite all my energy into discrete fv divider either, I choose the fastest routes as a coward as I am, using the 555's and next the IC's are about to come. It bugs me the 555 is not up to the task. Aaah.
- The 20MHz osc is the test osc ! I have other osc at different fv, some are greater some are less. I have one for ex at 40MHz. So our circuit must read up to 100MHz or more, to be able to deal with all the common osc values. I also have a lot of unknown values, which was the starting point for all this adventure here. Keep this little detail in mind all the time. FUN, right? Hahahahaha.

 

[marconi]

q12x Here is 74LS00 crystal oscillator which you can make when the box of ics arrives. Now you have three circuits you can make to test your crystals with.

Here is the circuit which uses three of four 2 input nand gates in the 74LS00. The fourth gate is unused so its two inputs are connected to 0V so that they do not float. The crystal is in the series resonance mode so low impedance at 20MHz.

I will look at the ics in the box to you and think about which one to use to do the division of fv and then construct the circuit. I am a bit slower off the mark than you are so be patient. I like to read the datasheets. I quick glance at the 74LS93 4 bit counter specification and it looks like it can operate the first divide by 2 stage with an input between 32 and 42 MHz so it might cope with your 40MHz crystal if the crystal test rigs will still perform at 40MHz. The last circuit using the 74LS00 was oscillating at 32MHz without the crystal in circuit - need to check again though to be sure.

https://www.ti.com/lit/ds/symlink/sn5400.pdf?ts=1653117913729

 

[_q12x_]

Ive redrawn your circuit, to make it clear (for me).
This is not actually simulating anything, I use it just for drawing (and clarifying).
I think I get you now, thank you for it !!!

 

[marconi]

Ive redrawn your circuit, to make it clear (for me).
This is not actually simulating anything, I use it just for drawing (and clarifying).
I think I get you now, thank you for it !!!
View attachment 97759

Vcc at 5V and 0V go to pins 14 and 7 respectively - but you knew that - just wanted to be careful.

If you make a test rig with a known frequency crystal you could check it is working if you have a radio with a short wave band by tuning in to the weak signal from the circuit. I think short wave/HF is something like 3-30MHz if I remember well.

 

[_q12x_]

See if you can find something that will register a 100MHz and can split from that down. I mean with discrete components. If its too much, I'll understand. And remember, we are playing until something cracks. Unfortunately I am unable to read and test anything with such high fv on any of my devices I have. But you have that cool osciloscope ... mmm. My idea is simple. If we can make a circuit with discrete components that will split from 100Mhz down, we are good. Else, we will stumble over various little shi.ts like my 555 craping itself when I need him most. Haha.

 

[_q12x_]

Vcc at 5V and 0V go to pins 14 and 7 respectively - but you knew that - just wanted to be careful.

+7V(Max) Vcc to pin4 and gnd to pin 11.
I don't know anything, I just look up in the datasheet.
(Sometimes) my biggest mistake is to presume, and I still have to learn to not doing it that often myself.

 

[_q12x_]

Mister @pc1966 and I were looking at this circuit for some time.
Flip-Flops Using Discrete Transistors:

I know it looks a bit full... I want you to try it at 100MHz and see if it can split it in half I guess, so its Q will be 50MHz. If it will do it, I will start making some of them. You are making it on breadboard, not definitive board on cardboard or fiberglass like I do it. It will really take you some minutes to check at what is the maximum fv can be used. It will be great if you have a fv variator of some kind... that will tell us the maximum range it can go.
I could make it myself but I have to make a couple of them, to really bring down the fv to my devices level that I have here. And I probably will, because it will most probably be too much for you. Will it?

 

[brianmoooore]

Nice to see proper resistor symbols have fund their way into this thread!

 

[_q12x_]

Nice to see proper resistor symbols have fund their way into this thread!

 

[brianmoooore]

Nothing American about it. Was the UK symbol as well, until a meaningless rectangular box was foisted upon us by some committee or other.

 

[_q12x_]

Russians, man, russians ! Haha

 

[pc1966]

a meaningless rectangular box was foisted upon us by some committee or other.

It was to make it easier for pen plotters in the early days of CAD drawings I believe. Now it is slightly irrelevant.

 

[marconi]

+7V(Max) Vcc to pin4 and gnd to pin 11.
I don't know anything, I just look up in the datasheet.
(Sometimes) my biggest mistake is to presume, and I still have to learn to not doing it that often myself.
View attachment 97761

You are right and I am right! I was talking about the 14 pin dual in line pin layout which is the type I use and have sent you.

 

[_q12x_]

Good morning signori @marconi
- I was looking only on the pdf that you post it, later I realized that you may have different package than in the datasheet and you are mentioning them. But I didnt had the chance to add more comments because the timeout for comments on this website will cut your ideas off. Its a good idea to let comments on, not everyone is english speaker and everyone makes mistakes that can be repaired, if is given the chance, im speaking to this website managers/designers.
- It appears all my initiative with reading a 20MHz Before the IC's arrival fail. Because, it appears, the discrete components circuit has some limitations from its RC in there, and the 555 is not up to that fv, and I need a much higher fv than 20 anyway, at least 100MHz to have a normal range of testing these osc's. What matters is that we tried, we moved fast enough and we got results. In part2, we will use your IC's. Im curious if they will raise the the task, until the actual fv counter arrives. Another against time run. I am particularly against making anything against time and in rush !! I like it slow and precise. But this is a strange coincidence how everything falls this way. And the time is not that fast anyway, so about 1 week for an experiment is plenty for me anyway.

 

[marconi]

Im curious if they will raise the the task, until the actual fv counter arrives. ???

 

[marconi]

q12x : Since you mentioned the problems caused by resistance and capacitance in integrated circuits operating at high frequencies or switching speeds I thought you might enjoy reading this article:

In processors and graphics cards, what limits your clock speed? - https://techunwrapped.com/in-processors-and-graphics-cards-what-limits-your-clock-speed/

Another limit is temperature rise of the ic. Because many yet small capacitors are being charged and discharged very frequently/at a high rate - Giga Hertz in some devices - there is a significant heating effect caused by the many but small currents moving the electrons in and out of the capacitors. You know that when a current flows through resistance there is heating which causes ics like processors to warm up. So they are fitted with heat sinks and fan blows across them otherwise they would overheat and burn out. Thus, keeping the ventilation holes of your computer unobstructed is a good idea. (In the computers I worked on in the 80s with many microprocessors the air was cooled first by passing over fins cooled by chilled water at 5C.)

 

[pc1966]

I could make it myself but I have to make a couple of them, to really bring down the fv to my devices level that I have here. And I probably will, because it will most probably be too much for you. Will it?

I tried a quick SPICE simulation and (a) it did not work properly (toggled only first time) and (b) even then you are looking at switching times of around 10us, placing the max speed at below 50kHz even if it had worked as hoped!

 

[marconi]

Here is a 74HCT73 dual jk flip flop in cascaded toggle mode with first ff being clocked at 20MHz and scope showing 2Q output of second ff. thus divide by 4 to five 5MHz I do not have any HCT93s to hand.

 

[_q12x_]

Im curious if they will raise the the task, until the actual fv counter arrives. ???

Im curious if they will raise to the task, until the actual fv counter arrives. See? Small shht like this I am not allow to repair in my previous postings because this website is made against user !

q12x : Since you mentioned the problems caused by resistance and capacitance in integrated circuits operating at high frequencies or switching speeds I thought you might enjoy reading this article: In processors and graphics cards, what limits your clock speed? - https://techunwrapped.com/in-processors-and-graphics-cards-what-limits-your-clock-speed/

And I did enjoy it. I do like MCU's, and I only worked with PIC's so far, and very limited range and very few applications I used them. I didn't go nuts with them as I wished when I discovered them in my youth. But they remain a fascinating literature for me. So the RC problem in CPU's, conform to your article, is due to the micro-wiring length and thickness, remaining constant over time while the transistors got smaller. If I understood it correctly. Very interesting. Yes. Actually mister @pc1966 spotted that RC problem in the last FF (flipflop) circuit and I concluded on his finding.

Another limit is temperature rise of the ic. Because many yet small capacitors are being charged and discharged very frequently/at a high rate - Giga Hertz in some devices - there is a significant heating effect caused by the many but small currents moving the electrons in and out of the capacitors. You know that when a current flows through resistance there is heating which causes ics like processors to warm up. So they are fitted with heat sinks and fan blows across them otherwise they would overheat and burn out. Thus, keeping the ventilation holes of your computer unobstructed is a good idea. (In the computers I worked on in the 80s with many microprocessors the air was cooled first by passing over fins cooled by chilled water at 5C.)

I admit, I didnt got this interested like you did about the internals of a CPU. Very nice explanation ! I like it. As a fact, everyone got amused when coming into my room and seeing my desktop PC case with one side open all the time and an external black fan blowing into it (actually towards my 2HDD), and they asked me "is it broken?" and I respond, "no, it is properly cooled". I got into this arrangement from my very first computers and it stay with me until today. I also highly recommend it. The downside it is getting dusty, quite quickly, so 1/year I do a total cleanup, I take out the processor, re-paste it, clean everything from dust, especially its heat sink radiator, that usually develops a fur on it, like a little rat.

By the way, signiori @marconi you worked in computers in the 80's you said, what did you do? Also tell me your expertise, what you did and know the best, what you master, and what you really enjoy. I realized I know nothing about you and now is a good time to ask. The same question to mister @pc1966 as well. Im equally interested.

I tried a quick SPICE simulation and (a) it did not work properly (toggled only first time) and (b) even then you are looking at switching times of around 10us, placing the max speed at below 50kHz even if it had worked as hoped!

Thank you for trying that. I am not that good in LT Spice. I have it on my pc but i cant say im good in it. Only to a point and that is a very low point.

Here is a 74HCT73 dual jk flip flop in cascaded toggle mode with first ff being clocked at 20MHz and scope showing 2Q output of second ff. thus divide by 4 to five 5MHz I do not have any HCT93s to hand.

Ahaa, an experiment, very interesting result !
See if you can obtain my results: 1/10, then 1/100, then 1/1000 divisions. As a challenge of course. Also I highly recommend to use the 555 circuit that I used. Extremely helpful but to a limit as we all know it now.

 

[pc1966]

Thank you for trying that. I am not that good in LT Spice. I have it on my pc but i cant say im good in it. Only to a point and that is a very low point.

Simulations are useful but ultimately not always understood by those doing them. Generally speaking:

• If a simulation tells you it won't work, almost certainly it won't work!
• If a simulation tells you it will work, it might - you will need to try it to be sure.

Of course as you get to fancier tools, especially those that will extract PCB layout in to electrical parameters to replace the "wires" in the model, you get closer to reality, but often if is not practical to model everything that way.

More subtly you can get situations where you have two (or more) aspects to the circuit with very different time-constants, for example an RF transistor that can (and will) operate in the GHz region so needs pico-second time-steps to model the changing voltages & currents, and a bias control system that has millisecond time constants, so you need to run the simulation for billions of time-steps to complete it, leading to massive CPU effort and/or the simulator failing to converge normally.

Mathematicians have a term for this problem and lots of fun looking at ways of dealing with it:

Stiff equation - Wikipedia

en.wikipedia.org

And that is even before we get in to non-modelled aspects of the devices!

So a simulation is really about avoiding the alpha breadboard stage to see if it will do anything useful, thus you get to the beta stage quicker and cheaper, and then you can build your PCB or other more realistic prototype to confirm (or otherwise) that you are on the right track for success.

 

[marconi]

q12x Attached are two short clips. The first shows a divide by 10 counter with a 20 MHz input and 2 MHz output using a 74LS93 like the ones I have sent you. The second clip is this same divide by 10 counter now with its input at 5MHz taken from the output of the divide by 4 counter I made earlier using a 74LS73 - total division by 40 thus 20MHz down to 500kHz. You will be able to do the same soon. Using the 7493 you can divide by any whole number between 2 and 16. Adding 7493s so one provides the output for the next enables further division to be done as I have shown you. Hence my suggestion you build an electronic clock using a crystal as its timing source.

 

[_q12x_]

q12x Attached are two short clips. The first shows a divide by 10 counter with a 20 MHz input and 2 MHz output using a 74LS93 .. The second clip ..total division by 40 thus 20MHz down to 500kHz...

to @marconi : very cool ! I like it. And thank you. But you are still limited by the maximum IC fv. Higher than its maximum and you are in the same situation as I am. Btw, what is he maximum fv it can see this 74LS93 ? Actually I will check it as well.

CP0 meaning Clock (at) Pin 0 and is an inverted CP0 with the bar on top. I wonder why 2 Clocks? Maybe because it has 2 sections? and CP1 is half speed? Hmm, very strange. So our CP0 is up to 32MHz. But if I feed him a 42Mhz crystal is dead in the bushes like my 555. But is good for all the crystals under its max value which is still good enough for me. I mentioned already, having a level of 100MHz is good because I can test all my osc's, especially those over 32MHz. But maybe 'my majority' is under 32 so everything will be good? I will see the 'majority' until after I build and test everything. What a strange project. I really didnt want to spent even 2h on it, and it turn out to spent 2 months, haha. Strange, right?