Make a very simple test for me

I did what you told me.

pc1966 said:

If you can get a watch crystal of 32,678Hz and try with higher resistance values to match that sort of crystal (suggested above) then you might see it.

Click to expand...

Everything I USUALLY test, especially in low power electronics, signal or logic, I do it @ 5V from my varPSU. So now I test as well. I tested probably more than half of the OSX's I have, known and unknown values, and nothing showed on my DSO138 osc. I even have 4 of those cylindrical you showed me in your link, and nothing. They are (probably) too fast.

Edited:
- I still didnt managed to make your suggested circuit yet. I am very happy that I understand the limit of my osc now. Very happy. That 200kHz sais it all. It is dinky !!! And no matter what testing circuit I make, not even your suggested one, the osc will give me a finger either way.
So it was a very good step to do, in purchasing that fv counter I did some days ago. Which cost me 10$ by the way , comparative to 400$ from your link. But I WISH I have that 400$ one. This one will be another dinky 10$ ebay tool. Oh well, I dance with what I have, right?

Check that book of yours, see if you can find a 1/10 or a 1/100 fv splitter circuit in it !!!!
The analog way !

_q12x_ said:

I have an Ingeeneerious idea !
Is there a way to SPLIT the fv of a BIGger OSX into a smaller fv? Just to bring it down under 200 kHz? Just enough to measure it with my dinky osc? Ha?

Click to expand...

Yes, there are at least two ways to do that:

• Heterodyne the unknown oscillator with a known one and then look for the sum or (more useful here) difference frequency
• Use a divider chip to get a fraction of the oscillator frequency

In your case the divider option is far cheaper and easier to investigate. Look for the 74HC4060 as it will run 20MHz at 5V, is cheap, has a gate that makes for an easy oscillator circuit (or even as an input buffer/amplifier to take the signal from our transistor set-up) and offers divide ratios of 2^4 to 2^14 (with a one gap). So 20MHz comes out of the final stage as 1220Hz.

This data sheet as an example parallel resonance crystal oscillator in Fig 13:

For 20MHz or similar then R2 = 2.2k is reasonable. For 32kHz crystal then make R2 = 100k to 220k. Rbias should be 1M usually, but for 32kHz there is some advantage of using 10M (or 1M + 1M with small 1nF capacitor to ground from junction between them).

pc1966 said:

Look for the 74HC4060 ...

Click to expand...

Well, is not practical. Your IC idea is good but is too late.
Because if I will buy this particular chip now, my fv counter will have been arrived until this chip arrives. What I mean, is there a common way, a circuit way, a easy-er way, a quick and dirty way, a rough approximation way? I really dont need the decimals after the dot. Just the big number and its good enough. So, can you find or think on a circuit from basic components or very common chips like 555 or opamps, that will successfully divide a fv ? This is what I mean. Also use that interesting book for this specific task.

Hey, thank you all for the commitment and for debugging this problem with me.
You really helped me, especially by figuring out the 200kHz limitation of the osc.
Thank you very much !

Following your suggestion, using a dedicated chip..... I get involved into research and I find this:
And....I have a bright idea...
After reading about this process, I understand that division by 2 is done using a D flip-flop circuit.

I understand it is a digital logic operation.
And the bright idea is to actually build a D flip-flop circuit. Or use a chip that may already have some ready flip-flop pins.
I have a small list of personal chips I can put down for you to look over, and if you spot any IC that will fit this task, then poke me. I already seen one CD4013 x1 dual D flip-flop but I have only 1 of it.
See if you find others.
Until then, I will concentrate on reading how to make a D flip-flop from discrete components. And possibly make a circuit. Mmmmm....

Hmmm... I find Frequency divider using 555 timer !!!

q12x : Good evening. I have been occupied today to be of any help(?) but can see that some very able folk have responded.

What is your project goal now please? You have bought a frequency counter which arrives soon. You have some quartz crystals which you want to confirm work and their resonant frequencies. Thus, it seems to me you still need a test rig to put these crystals into to make them oscillate. And you need a way of connecting the test rig to the frequency counter to measure their resonant frequencies. I am happy to help but need some clarification on what next - the test rig?

But before all that - what do you intend to do with these crystals?

The finest profs on the EF
Just saying hello thats about my input.
Way over my little ole head just a mere installation electrician.
I will be the first to stand on one side of the corner.

_q12x_ said:

And the bright idea is to actually build a D flip-flop circuit. Or use a chip that may already have some ready flip-flop pins.

Click to expand...

You can build them, but it is quite a few parts for a single stage and given the expected crystal frequency of 20MHz and your scope's limit of 200kHz, to see something approaching a square wave you need to show at least the 3rd harmonic, and ideally 5th, so you would want a final frequency of around 200kHz/5 = 40kHz.

So your divider would be 20MHz / 40kHz = 500 and closest binary option is 512 = 2^9 = 9 flip-flop stages.

_q12x_ said:

I have a small list of personal chips I can put down for you to look over, and if you spot any IC that will fit this task, then poke me. I already seen one CD4013 x1 dual D flip-flop but I have only 1 of it.
See if you find others.

Click to expand...

Most of your ICs are of the CD4000 series, they are only able to clock in to a MHz or so. You need to look at the 74HC series (or 74LS) to get 20MHz or more capabilities. Generally 74HC is easy to work with, some others are not so easy (restricted voltage range, or very fast switching so issues on breadboard use, etc)

The 74HC4060 is cheap, if getting one then buy at least 2 and check it is the DIP version, not surface mount package. It is finding a place that won't charge you a stupid amount of postage that is a challenge!

_q12x_ said:

Hmmm... I find Frequency divider using 555 timer !!!

Simple frequency divider

Electronic circuits, projects and tutorials. PCB details, microcontroller projects, power supply, high frequency and audio circuits.

www.circuitlib.com

Click to expand...

That sort of a circuit only works well for a limited frequency range. A typical digital divider works from "DC" (clock stopped) up to the clock limit of the IC (tens of MHz input for the 74HC family).

7029 dave said:

Way over my little ole head just a mere installation electrician.

Click to expand...

Don't put yourself down, you contribute a lot on other matters!

marconi said:

q12x : Good evening. I have been occupied today to be of any help(?) but can see that some very able folk have responded.

What is your project goal now please? You have bought a frequency counter which arrives soon. You have some quartz crystals which you want to confirm work and their resonant frequencies. Thus, it seems to me you still need a test rig to put these crystals into to make them oscillate. And you need a way of connecting the test rig to the frequency counter to measure their resonant frequencies. I am happy to help but need some clarification on what next - the test rig?

But before all that - what do you intend to do with these crystals?

Click to expand...

Hello my friend and salutations from Romania. I believe you speak in name of everyone and some clarification might be in order from my part. Indeed my frequency counter is on the road. That is plan B that is going to happen. But until it arrives, in 2-3 months, I think I can PUSH this thing a little bit. You know? That's my goal here. And by pushing, I mean to make something that works, even if I have to make it from different parts or even circuits. For example, a circuit made from discrete components that will make a single D Flip-Flop stage in the 10 stages that I calculated.
Here is my plan:

20000000 = 20M
2000000 = 2M
200000 = 200k
20000 = 20k =/1000

2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
2^5 = 32
2^6 = 64
2^7 = 128
2^8 = 256
2^9 = 512
2^10 = 1024 =10 flipflops

20k or20000 means 20000000/1000 and 1000means 1024 in binary so 10 flipflops
Why 20k? because I think I have larger than 20M, I think Ive seen one at 50M.
Somewhat being in the safe side, and also easy to calculate if you roughly multiply by simply 1000 in your head.

I really don't think the "test rig" as you put it, is the biggest problem anymore. I think the "splitting" as I call it, is the bigger issue. Because as we discovered, my DSO138 is limited to 200kHz so we need to bring everything down to it's level of measuring. That's it. Simple.
And for this, I'll have to use what I have on my hands. Some chips if im lucky or the obvious way, build a couple of discrete D- flip-flops. I'll make a factory of production these days here in my room. Haha. You probably remember how I build my circuits, using cardboard and pieces of bended sheet metal that makes pads for soldering. Very shi..ty ones but good enough for the amount of experimentation I am doing.
What you are wondering so hard now, is why do I want so bad to PUSH it, instead of waiting for my new fv counter? Well, because why not.
If you are good enough to get involved into my small project here, because this will be hard to make anyway. Is to find for me a very good D flip-flop discrete circuit that I can build using my components I have in storage. Ideally is to build it from 555's because I have 100 both DIP8 and smd SOT-23. I am researching myself this possibility at the moment.
I hope is clear enough. If more clarifications needed, just ask me.
- Saying hello back to mister @7029 dave

pc1966 said:

....
Most of your ICs are of the CD4000 series, they are only able to clock in to a MHz or so. You need to look at the 74HC series (or 74LS) to get 20MHz or more capabilities. Generally 74HC is easy to work with, some others are not so easy (restricted voltage range, or very fast switching so issues on breadboard use, etc)

The 74HC4060 is cheap, if getting one then buy at least 2 and check it is the DIP version, not surface mount package. It is finding a place that won't charge you a stupid amount of postage that is a challenge!

Click to expand...

Yes... I am new to this chips you are speaking here. I will start looking for them and probably even buy, if they are not expensive for 100pcs as I usually buy all my components. It is good that you tell me about them. Thank you.
But remember, I will start with whatever I have in hand at the moment.
I believe you are trying to tell me it will not work using discrete D flip-flops or the 555 version of it, because they will not be fast enough for the 20M (or more) speed. If this is the case, please be clear with me now, before I start doing anything ((stupid)ly hard and slow). Its a ton of work but in a few days I think I can do it.
Have a good night (to everyone) and see you tomorrow.
Thanks so far !

q12: Good morning. Thank you for your nice email. Gathering dust in my shed I have some 74LS273 octal D type flip flop ics.

https://www.ti.com/lit/ds/symlink/sn54ls273-sp.pdf?ts=1652639946774&ref_url=https%3A%2F%2Fwww.google.com%2F

I will post you some as a gift. Please private message me your address or somewhere to post them to from where you can collect them.

Each chip will divide by 2exp8.

https://www.electronics-tutorials.ws/counter/count_1.html

I will include some 74LS14 Schmitt triggered inverters chips so that you can input the 20 MHz sine wave and output from it a square wave to clock the 74LS273.

https://www.ti.com/lit/ds/symlink/sn74ls14.pdf?ts=1599590379543

You could use a circuit like this using two Schmitt triggered inverter gates as your test rig for the crystals which would in turn output square pulse to drive the frequency divider:

https://electronics.stackexchange.c...nverters-in-quartz-crystal-oscillator-circuit

I see that a later circuit uses 74HCU04 inverters. I will see if I have any. I know I have some 74LS04 ones.

https://www.infinite-electronic.kr/datasheet/54-74HCU04D.pdf

http://web.mit.edu/6.111/www/f2017/handouts/labs/74LS04.pdf



Regards

Marconi