how to check crystal oscillator?

Typically this is done with an oscilloscope. A frequency counter can be used as well.

If anything is oscillating at 4 milliHertz, then you have approximately

4 minutes per cycle. Any multimeter, even a non-special DC multimeter should suffice to detect its operation.

He said megahertz(10^6), not millihertz(10^-3): BTW: anyone know what you would use a millihertz clock for? Just curious.

He said 4mhz, but probably should have been 4Mhz

4mhz = 4 millihertz 4Mhz = 4 megahertz

sQuick..

4 millihertz would be one cycle every 250 seconds. My guess is that no one would even make a part like that and it would have to be built. Anyways, testing would be easy...

On 14/01/2004 Airy R. Bean opined:-

He said _crystal_, therefore it would be a fairly safe assumption to make that mhz meant Mhz not milliherz.

No, he said milliHertz, "mHz" and not megahertz, "MHz".

Actually, I believe it should be 4 MHz since Hertz is a proper noun.

But so are, "volt" and, "amp"?

I suppose that's why they are V and A and not v and a. At any rate, volt and amp are not the actual names Volta and Ampere are.

Yes. Nevertheless I agree with the original assertion that, "Hertz" deserves a capital.

The way I got it many years ago is that a name used as a unit is NOT capitalized when spelled out, but IS capitalized when abreviated. Therefore, 60 hertz and 60 Hz is the rule. Same with volts and amps.

120 V, 120 volts and 10 A and 10 amperers. --Phil

That probably fits in with what most of us have encountered, but it seems to be a strange use of language; as strange as using, "antennas" for the plural when, "antennae" was known to be correct; and which was correctly adopted when the term, "antenna" was itself adopted to describe insects' feelers. (The original Latin noun meaning the yard-arm of a sail)

I just wanted to see how long it would be until somebody gave the poor guy a straight answer to his question...

Simple answer...get a receiver that tunes to the frequency of your crystal and listen for a carrier.

Slightly more complex...get a special "receiver" called a spectrum analyzer and look on the 'scope for a spike of energy at the frequency of your crystal.

Jim

Good critical point, OM.

There's always the old favourites of the GDO and absorption wavemeters, or even a 100 pF, In914 diode, and a multimeter.

Then you'd be wrong. When a unit named after a person is abbreviated the unit is capitalized. When it is written out the unit is not capitalized. So it's "4 MHz" or "four Mega-hertz" It's the same with amp(A), volt(V), watt(W), ....

Right or wrong? Or just a question of personal style?

Insofar as the name given to a unit is a proper noun, it would seem correct to capitalise it.

You've been proved WRONG! again, Evans... Have you ever posted anything with a grain of truth or fact in it?

100% wrong!

SI is not about personal style. ...rather the opposite!

It may be a nitpick, and I wouldn't have raised the issue except that you were correcting others, while being quite wrong yourself.