A curiosity component

Thread Starter

q12x

Joined Sep 25, 2015
881
I originally thought this is a relay. It had only 4 pins on it, boxed in a metal case and the label was completely erased.
I actually store it with all the old relays in the same box.
The pink markings here are the external pins that you could access.
20220511_130944.jpg
This is a very old component probably from the 90's or even 80's.
You can see the metal case and it's completely erased label. The red-brown pieces in the right is the potted fragments. Everything was potted and encased. That red-brown material is actually rubber, very soft and it was not brittle, after all this time.
Inside, for my surprise, I find these 5 metal cases looking LIKE high-frequency oscillators . They clearly have a color code marked on them and probably some polarity along with it... Im guessing big time here. I know in the 80's and 90's I got some diverse components, and mostly transistors that were made in the soviet era, and all they had color markings like these things here. They didnt had a number like we are used today, they had a small blob of color paint on them. I am from Romania, by the way...
20220511_130922.jpg
Im mentioning those old transistors because these 5 metalic components here are also having 3 legs each.
But the middle leg is cut for the 3 in the middle and only the side ones are used with the middle pin as an external contact pin.
All appear to be linked in series.
Very strange (for me). I never encounter such thing before.
20220511_130943.jpg
Between 1 leg of each metal component and the external metal case, is connected a capacitor, probably in the order of pico F, I didnt measure them, but by the look of it. Also,all the metal cases (the 5 small ones) were soldered with a big blob of solder at their top.
20220511_130902.jpg
Each metal case have no inscription on them, no number, no letter! Only that color marking and that's it.
20220511_130927.jpg
My question to you is :
- What they are?
and
- How to test them?
If they are transistors, that is simple to test, I have 2 or 3 ways for that. But I doubt they are transistors because of that middle leg cut out for 3 of them in the middle. I higly suspect they are high-frequency piezo oscillators, but how I can determine their frequency? I didn't dealt too much into frequency area of the electronics. I have a couple of piezo oscillators and I know for sure they have 2 pins, because I used them as external oscilators for the old 16F84 PIC MCU some 10 or 20 years ago. And they were 16 or 20khz if I remember right.
There are no wrong answers here, a simple guess is fine for me.
Im curious if they can be re-used and also to find their original value.
Thank you.
 
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Thread Starter

q12x

Joined Sep 25, 2015
881
Are any of the terminals connected to the cases? They look like crystals to me.
Each leg of the 5 components - so 5 legs in total- are linked to the big metal case through a capacitor. But not directly. The other legs are soldered in series with the next component in series. Only the start and the end components have their first leg soldered in series, middle leg and the 3rd leg as pins for external contact.
It is a very strange thing.

I agree with Marley. I think it is very likely to be a 10.7 Mhz crystal filter as this is a common IF frequency for VHF receivers.
This is an example of one.
Les.
Yes, I think you nail it !
"Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter."
What it is good for? For radios like those old walky talky?or police communication devices?
 

LesJones

Joined Jan 8, 2017
3,701
It could be designed for other frequencies than 10.7 Mhz. For example I think (From memory.) The Pye PF70 transceivers used an IF of 23.0 Mhz. If you plan to build a receiver using it you would need to know what frequency it was designed for and if it's bandwidth suited your requirements. You could get an idea of it's frequency by building an oscillator using one of the crystals and measuring the frequency. For a 10.7 Mhz filter the crystals would be a little below and a little above 10.7 Mhz.

Les.
 

Thread Starter

q12x

Joined Sep 25, 2015
881
The crystals may have their frequency printed/stamped on them.
I looked on all sides and they are not marked in any way. Again, this is MOST probably before the letters and numbers markings as we all know it today. It was sufficient back then to have a simple dot of color and not complicate things. I love that mentality actually, haha.
You could get an idea of it's frequency by building an oscillator using one of the crystals and measuring the frequency.
If its a small circuit, then yes I will build a tester. But if is too big and complicated circuit... grrr.... I will throw them into my "unknown" crystals oscilators bag. I have a few more actually, beside these 5, in the same way, unmarked or some very un-identifieble markings. Not that many but wouldnt hurt to actually have their values known.
Can you post a circuit that you think of?
 

SamR

Joined Mar 19, 2019
4,121
As @Marley said. They look identical to some HF CW Notch filters I've used. Used to reduce the bandwidth to dial in on narrow CW signals in a noisy bandwidth. Typically, 250 - 400Hz bandwidth. Wider for SSB.
 

LesJones

Joined Jan 8, 2017
3,701
Here is a crystal oscillator that I built about 50 years ago to test crystals and as a 10.7 Mhz marker. I traced it from the unit I had built. I don't think any of the components are critical. You will probably find many circuits if you google "transistor crystal oscillator".
EDIT. Here is the circuit that I forgot to add to this post.
110522.jpg

Les.
 
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AlbertHall

Joined Jun 4, 2014
11,952
I looked on all sides and they are not marked in any way. Again, this is MOST probably before the letters and numbers markings as we all know it today. It was sufficient back then to have a simple dot of color and not complicate things. I love that mentality actually, haha.

If its a small circuit, then yes I will build a tester. But if is too big and complicated circuit... grrr.... I will throw them into my "unknown" crystals oscilators bag. I have a few more actually, beside these 5, in the same way, unmarked or some very un-identifieble markings. Not that many but wouldnt hurt to actually have their values known.
Can you post a circuit that you think of?
There are some of these around which will make the crystal oscillate and measure the frequency.
https://www.ebay.co.uk/itm/393932390595?hash=item5bb83340c3:g:H2UAAOSwUqhiB5Ii
 

SamR

Joined Mar 19, 2019
4,121
Yup, I have one and they work very well for their price... It's not research grade by any means but a good go-nogo tester.
 

shortbus

Joined Sep 30, 2009
9,322
I got some diverse components, and mostly transistors that were made in the soviet era, and all they had color markings like these things here.
I know every one is saying crystals but could they actually be transistors? Transistors used as diodes/rectifiers?

" Diode-connected transistors are used in current mirrors to provide a voltage drop that tracks that of the other transistor as temperature changes.[2] They also have very low reverse leakage currents " From-
https://en.wikipedia.org/wiki/Diode-connected_transistor
 

sagor

Joined Mar 10, 2019
672
It may be what's called a "5 pole crystal filter", commonly used to filter RF signals in a radio (usually on receive). It may also be an IF filter, to shape and filter either a receive or a transmit signal.
The location of this filter on the circuit board would give a hint as to what it really is.
The size of the metal can suggests it is more likely an IF filter, probably a 10.7Mhz filter commonly used in many FM radios
 

Thread Starter

q12x

Joined Sep 25, 2015
881
Here is a crystal oscillator that I built about 50 years ago to test crystals and as a 10.7 Mhz marker. I traced it from the unit I had built. I don't think any of the components are critical. You will probably find many circuits if you google "transistor crystal oscillator".
Les.
Where? I dont see your circuit. Or if you post it and delete it, I didnt had the chance to catch it on time. I got to sleep after my last page check , and it was before your post. You can always send me something important through PM (Private Message) which is personal and not public. And it can remain there forever because only you and me have eyes on it. Don't be afraid to use PM, its a very useful tool, from the beginning of the forum era. Before forums, they were so called "chat" or mirc". Go on wikipedia and see im right, read the introduction text about "mirc". I catch those begining days here in Romania, and they were sensational. Americans of course they were more advanced, they had "pagers", mobile chat devices. We didnt. Anyway, too much details, right? Haha.
I will take your advice and google for this tester for oscilators right now. Thank you, it's a good idea that for some reason I didnt think of spot on. And is cheap, exactly how I like it.

There are some of these around which will make the crystal oscillate and measure the frequency.
https://www.ebay.co.uk/itm/393932390595?hash=item5bb83340c3:g:H2UAAOSwUqhiB5Ii
The 10£ device is a good idea, but I will try variant A first, building one from scratch, hopefully. If I will not get succesfull, then your idea will be variant B. The thing is, I didnt used crystals oscillators that much in my life, a couple of times and for extremely dedicated and specific circuits, in the PIC 16F84 case and it was the only case I used them and I start gathering them from scrapping, because I thought I will try other MCU's in the future with different clock oscillations requirements. I never did, but the thought remained. I also never find or searched for any other useful application of a crystal oscillator. I am a beginner with them, even if I used them 20y ago.
 

Thread Starter

q12x

Joined Sep 25, 2015
881
So, my first circuit for testing a crystal oscillator I find is this:
"Oscillator Circuit of The First Quartz Wrist Watch"
Oscillator Circuit of The First Quartz Wrist Watch.jpg
But ... bad news, my golden best of the best, oscilloscope DSO138 is not doing anything right.
I had high hopes for this circuit. I used 10k for both Rc and 1k for both Re. And I used BC548 for both Tr.
I used a known value of a Quarz of 20MHz. 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 influence the results.
Next, I will have to make another circuit, a bit more complicated in components count.
 

Thread Starter

q12x

Joined Sep 25, 2015
881
Ive tried these other 2 circuits and... no good results, at least from my golden oscilloscope.
20220512_151926.jpg
I believe my golden sensational super mega oscilloscope is not sensitive enough. It is a generic and limited tool what I have here. Is my opinion. The P1 probes give me the best result but only when I touch the probe metal with my finger. A very nice and tall square wave. In P2 mode, it was oscillating by itself without me touching the probe to get an osciloscope reading. And then I had the bright idea to take out the XT oscilator from the circuit and measure again. Guess what, the same result. Haha. So with or without the XT oscilator in the circuit, I was getting the same signal. Blah. What a failure.

Then I made the second - on the right- circuit, and that didnt work at all, but I used my awesome imagination this time. Theoretically, if we apply + and - on the XT oscilator pins, we should get a vibration, right? The (-)negative part is through the Base-Emitor of the transistor. And the Led is just a cheap indicator if the base is open. I did osciloscope the hell out of this one as well, but... again, Im not convinced my osciloscope is doing what is right.
See if you have some success with anything.
Ive always used the same known value XT oscilator at 20kHz. Because is written on it.
And everything was made on breadboard.
 
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Thread Starter

q12x

Joined Sep 25, 2015
881
There are some of these around which will make the crystal oscillate and measure the frequency.
https://www.ebay.co.uk/itm/393932390595?hash=item5bb83340c3:g:H2UAAOSwUqhiB5Ii
I think I understand now what I must have.
I just watched this YT video were he is preparing a small circuit and then is using a frequency counter as mister @AlbertHall already suggested. I am new to this and learning. So I start to understand this tool is good not only for XT'als but for a lot more things that oscillates, correct? And ... I just buy one.
 
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Thread Starter

q12x

Joined Sep 25, 2015
881
- Tell me something... the frequency counter, what else it is good for?
Besides counting the specific oscillations in a quartz crystal? I mean, can I count other kind of oscillations? Like the mains fv? (using a voltage divider) or... some 555 oscillating circuit? or a flip-flop? or a PIC MCU output? I mean, it is dedicated only for quartz crystals or it is universal, doesn't matter the source of oscillations?
I check its instructions and the signal amplitude is 30V. Exactly as my golden, one of a kind, oscilloscope DSO138. No direct mains measuring , got it. And also it says 0-50MHz range. Which means a very large spectrum of possible frequencies.
- Im doing a minimal research here and from wikipedia (Electromagnetic spectrum) I got that this instrument is up to ... VHF fv range. I cant measure light fv with it but for an average dude like me, i guess is enough? Hahaha...
1652507676726.png
For me, this device is something NEW and my best guess, a must have on my electronic bench.
So please tell me a story how you are typically use this for. And how often?
(I choosed this yellow version. Not the red version. I hope are the same thing.... we'll see.)
1652495380871.png
 
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