Check crystal working?

[umery2k75]

how to check crystal

I use these this kind of crystal in microcontroller project,usually 8051 with 11.0592Mhz. When my circuit is not working and I have to troubleshoot everything, I check microcontroller working with my IC programmer, it tells me whether controller is damage or fine.I don't know how can I check these crystals? I have found them faulty many times and only by replacing them, my circuit starts working fine.
**broken link removed**

 

[E-design]

crystal checker

All depends what tools you have available. Using a network analyzer it is easy. Otherwise build a crystal checker.
http://www.diy-electronic-projects.com/p218-Crystal-Tester

 

[umery2k75]

check crystal

I have seen the circuit, it seems good, I'll make it in a day or two.Can you define network analyzer more?

 

[E-design]

crystal checker with led

That circuit seems too complicated. I have come up with this circuit that you can make in 5min. I have tested it with crystals 2-20MHz and it works. LED will only light when there is oscillation, so it will only tell if the crystal is capable of oscillating. When there is no oscillation the voltage over the 180 Ohm resistor is too low to turn on the driver transistor. If you want to know the frequency you should use a scope or counteron node 6. Try and tell me if it works for you.

For 1MHz crystals the capacitors should increase (say 360pF each), but then you may have problems on the 20M side. Other common transistors should work as well (2N2222, 2N3904 etc.) It won't work with 32KHz watch type crystals as the loading on the crystal gets too much. It could be modified to use a JFET at this frequency.

 

[echo47]

crystal oscillator oscilloscope

A network analyzer is an instrument that measures the properties (such as S-parameters and impedance) of electrical networks. It is usually a large expensive precision instrument.

Here's a small web page showing one way to use a network analyzer to measure the properties of a crystal:
https://www.prc68.com/I/Xec.shtml

 

[pasicr]

check crystal in cct

Hi Umery,
I think the best way to check (solve) this problem is BUY NEW CRYSTALS,
no time loss, no to many money cost,
best regards

 

[E-design]

measure 12 mhz crystal with oscilloscope

Here is my circuit that can be used for checking watch type crystals.

 

[umery2k75]

how to check a crystal if it oscillates

@pasicr
Yes, this is what I had done today, bought dozens of crystals today

These circuits tells whether there's an oscillation or not, but I think if it has feature of telling the exact frequency, it would be very good, that is if a crystal is rated at 12Mhz, if I check this crystal and it give me the reading as 11.99Mhz so I can say it's 99% accurate.I mean can we check it in the same way as we check the resistances,capacitance and inductance by multi meters.

 

[mcs51mc]

to check a crystal

@pasicr
...that is if a crystal is rated at 12Mhz, if I check this crystal and it give me the reading as 11.99Mhz so I can say it's 99% accurate....

Strange mathematics
99% of 12MHz is 11.88MHz

Why not using a standard digital scope?
Problem is, what accuracy do you expect?
Any particular reason why you don't trust the manufacturer?

 

[umery2k75]

diy crystal tester

Oh I didn't do the mathematics I just wrote the rough figure for the 99%,
well I have digital oscilloscope from Tektronics, I didn't know if I could use this to measure the quartz crystal.I do trust manufactures.
I don't want to have high accuracy, error of 1-5% is fine to my work.I was just wondering :roll:

 

[feiutm9898]

crystal oscilloscope

I use these this kind of crystal in microcontroller project,usually 8051 with 11.0592Mhz. When my circuit is not working and I have to troubleshoot everything, I check microcontroller working with my IC programmer, it tells me whether controller is damage or fine.I don't know how can I check these crystals? I have found them faulty many times and only by replacing them, my circuit starts working fine.
**broken link removed**

Do you know how to use oscilloscope? Just put the probe to the crystal pin. You should see 11.xxxMhz digital signal. Very simple to do that.

Second, please check the peak-to-peak signal to make sure the peak voltage is correct.

In short:

(1) frequency
(2) Peak-to-peak signal

Why wondering? I have used this method many times to check the crystal.

 

[E-design]

mhz cristal tester schematics

Caution: The loading from a 10X scope probe will often be enough to stop the oscillator, especially where it uses a low frequency crystal with high internal resistance.

 

[umery2k75]

how to check crystal in microcontroller

I have used the oscilloscope many times, but I didn't know that it could measure the crystal frequency when not powered, as you have mentioned earlier that I must connect the probe to the crystal pin and check the desired parameters and probes contains some resistance,capacitance and inductance, as to make them possible to switch from X1 to X10 and they are passive in nature.So what makes the crystal excites to the 11.XXX Mhz.There must be some sort of voltage difference between the two probes to excite the crystal to produce the frequency, so how could probe do that.Does this mean a pair of probe has some potential difference across them?
Right now I'm making a project board for PIC16F877A and I'm busy in soldering the circuits from two days back.My work is almost complete now.I'll perform this experiment of your very soon and I'll post my findings.

 

[echo47]

how to check crystal if working

I'm sure feiutm9898 meant that the oscillator must be powered-up and running before you can measure it with an oscilloscope.

A crystal oscillator's frequency can be varied slightly by adjusting components in the oscillator circuit. Some circuits provide a small trimmer capacitor so you can easily fine-adjust the frequency to the desired value.

As E-design suggested, poking a scope probe into an oscillator's analog circuit could stop it. Even if it doesn't stop, the probe's capacitance will surely change the frequency. Try measuring the frequency at the oscillator's output, or somewhere down the counter chain. Sometimes you can hold the probe tip close to the oscillator without actually touching it, and still measure the frequency -- that won't disturb the frequency very much.

Most scopes aren't very accurate for measuring crystal oscillator frequency. A frequency counter would be much better, but again don't poke the counter's probe directly into the oscillator's sensitive analog circuit.

A crystal is somewhat fragile. When soldering, don't overheat it. Probably a good idea not to drop it either.

For a very crude check of crystal operation, you could simply connect the crystal between a sinewave generator and your oscilloscope. At the crystal's series resonance frequency, the signal should come through pretty strong. Tune carefully because the bandwidth will be very narrow, maybe a few kHz for an 11 MHz crystal.

 

[aupa]

how to check crystal

you can't be shure if the Xtal its ok using a scope.

the scope has an impedance that perturbes the signal.

i recommend u to use any of circuits above.

 

[umery2k75]

probing 12mhz crystal

feiutm9898 told me that oscilloscope can check the crystal.Yes, he was correct.I got successful to measure the clock frequency accurately upto 4 significant figures after decimal i.e 11.xxxx

As far as the oscilloscope probes are concerned, they are of high impedance they don't disturb the circuit and neither impose any external effect.

Oscilloscope is a better option, because it can show:
1)Crystal is working(Above circuits can also tell)
2)At what frequency is it working(Above circuits can't tell you, oscilloscope can tell you)

I have demonstrate you using oscilloscope to measure crystal exact frequency.

 

[Eugen_E]

crystal checker circuits

Generally you need to test only if it oscillates.
The frequency error it's under ±5kHz for crystals in the 1-25MHz range, and if high precision is needed you can compensate in software. The frequency may have an offset from the standard value, but it's highly stable.
To get a small error use high value loading capacitors or trimmers. The disadvantage of high capacitance it's higher current consumption of the uC.

 

[maxchirag]

I only want to check weather it Ocilates or not?,

what is the simple way to check that?

 

[Fragrance]

HI

Simple and best method is if you have frequency counter simply check frequency on osc out pin of controller, you will get same same frequency crystal on that pin which show crystal working fine

regards
Fragrance

 

[rakesh_rf]

hey,i wanna check crystal 0f 8.704Mhz,using network analyzer,plz help me,i wanna know more abt the test procedure