Is this a resonator, or an oddball?

[dr peppers]

I took this off a scrap board and wondered whether its an odd capacitor or a resonator, it only has 2 pins unlike a resonator but its does look like one.

The markings are 206f 05n, the 05 looks like the date code, it'd be usefull if it was a 200kc resonator.

I cant remember what part of the board it came off, there was some digital stuff on there so it might have been a clock generator.

Sorry about the pic, best I could do, the pin spacing is 0.3".

View attachment 61607

 

[MrAl]

Hi,

Wow, that's one of the worst pics i ever saw for trying to describe a part

To help, get a decent magnifying glass and hold it in front of the camera lens. I assume you have a digital camera with back LCD so you can see what you are focusing on. With the lens in front, focus and shoot. Might not be able to use the flash here though, but you'll get a much better macro shot with a few tries.

The pic as is does not tell us much because it is so blurry. If it was sharper someone here might recognize the part.

 

[dr peppers]

Tried it, but its hardly any better.

View attachment 61616

 

[PCBWING]

It is not like a resonator. Shouldn't you use a multimeter to measure it?

 

[Mr RB]

206f
Might be a 2MHz or 20MHz resonator. That's my guess. Connect it to a PIC and see the freq?

What equipment do you have? A cap meter should rule out it being a 206 (20uF) cap.

 

[MrAl]

Hi,

Yeah it does look a little long to be a resonator, but who knows.
That picture is a little better though, if you could get the focus just a little better.

The way some resonators are tested is they are simply connected across a CMOS 4069 inverter along with a parallel 1Megohm resistor. A second inverter is used as a buffer, the output frequency measured. Loading caps are typically 15pf to 30pf (one to ground on each lead of the resonator).
You could try i guess, not sure if this works at 20MHz too though.

 

[dr peppers]

An 'hct or 'act logic chip will go to 20mc's, might try that later.

I have an LC meter, never thought of that, doh.

 

[The Electrician]

I took this off a scrap board and wondered whether its an odd capacitor or a resonator, it only has 2 pins unlike a resonator but its does look like one.

The markings are 206f 05n, the 05 looks like the date code, it'd be usefull if it was a 200kc resonator.

I cant remember what part of the board it came off, there was some digital stuff on there so it might have been a clock generator.

Sorry about the pic, best I could do, the pin spacing is 0.3".

View attachment 61607

I would expect a resonator to have only 2 pins. If it had 3 pins I would think it was a ceramic IF filter.

Attached are 2 images. The first shows a 4 MHz ceramic resonator and a 47 pF capacitor. The resonator is the larger item.

The second image shows a sweep to 30 MHz of the transmission of the resonator between port 1 and port 2 of a network analyzer. Several resonances can be seen. The fundamental resonance appears at 4 MHz, which corresponds to the marking on the unit. The capacitor showed no similar multiple resonances.

Measuring it with an LCR meter isn't going to do much good unless the meter can measure at a frequency equal to one of the resonances. The unit in the picture measures as a 38 pF capacitor on my meter at 1 kHz.

However, you might be able to use another technique to determine if it's a resonator.

I was able to detect the resonances by simply connecting the resonator to the output of a signal generator, setting the output level to .1 volts to avoid damaging the resonator, and monitoring the level across the resonator with a scope. It has fairly high Q, so you have to tune the generator slowly to see the resonator pull down the generator output at series resonance.

 

[PCBWING]

resonator

...
I was able to detect the resonances by simply connecting the resonator to the output of a signal generator, ...

View attachment 61675

 

[dr peppers]

I connected the part to my LC meter to see if the markings corresponded to a capacitance (my LC meter tests at 50kc).

Thats a good suggestion about the sig gen and scope, I dont have a analyser but I do have the others so I could do that.

I just found a very similar part on another board, its longer and is marked with a higher number, the LC meter still doesnt make sense of that one either, but now I'm thinking that they are very high value resistors, 20megs and higher, so my meter will not measure them.
I could make up a circuit on breadboard, a voltage divider, and then buffer it with an op amp due to the high impedance and measure the voltage, but I think I'll just consign these to the misc drawer.

 

[Mr RB]

They are resonators (as myself and others have said). I have hundreds of them pulled from old equipment as they are one of the parts you can salvage very easily and are quite useful. They come in 2pin and 3pin styles.

 

[dr peppers]

Aha, so the bigger ones are lower frequency then.
Back out of the misc drawer and into the resonator drawer.

I recognize the Mr RB, I built one of your crystal ovens a while back, worked a treat.

 

[Mr RB]

The real big square epoxy ones are usually ceramic filters and typically found in RF circuits. The short rounded epoxy ones with 2 or 3 pins are usually resonators and are very common in anything with a microcontroller, and found within an inch or so of the microcontroller IC. There is another type of square resonator in a hard plastic square box pack, these are common in TV remote controls etc and usually a lower freq like 455kHz.

Congrats on the xtal oven. A few people have built that and liked the results.

 

[The Electrician]

Pictures of ceramic resonators:
https://www.bing.com/images/search?q=ceramic+resonators&qpvt=ceramic+resonators&FORM=IGRE

Pictures of IF filters:
https://www.bing.com/images/search?...hz&qpvt=ceramic+filter+10.7mhz&FORM=IGRE#x0y0

 

[MrAl]

Hi,


Yes resonators come in two OR three pin packages. The three pin packages include the load capacitors internally and so have a third ground lead.

 

[dr peppers]

So thats what the third pin is connected to.

I've replaced a few 455kc resonators in remote controls, they fail when dropped hard enough.

Thats a fairly comprehensive list of resonators and if filters, mine doesnt look like any of them.

 

[MrAl]

Hi again,

In the past i've never used a resonator i've always used crystals.
BTW some might have four leads but i havent seen any of those myself.

 

[dr peppers]

I used a resonator for a frequency standard project, a crystal didnt work as it wouldnt pull enough, the resonator did.