Digikey-measurements in Ø?

[ExpAnonColin]

Does anyone know what the measurements in the digikey catalog and on the site are?  I can't make heads or tails of it, seems to be either mm or cm but neither make sense.  All the symbols I see are "Ø".

-Colin

[Peter Snowberg]

The Digikey diagrams seem to be just about all metric. I've scratched my head over the same thing more than once.

The numbers marked "Ø" refer to diameter, usually of a mounting hole but also sometimes a shaft.

Take care,
-Peter

[ExpAnonColin]

cm or mm, or is it "either"?

-Colin

[Peter Snowberg]

Digikey (and Mouser too) just reprint images from the maker's spec sheets so the units will vary from part to part. Most of the time things are in mm. I guess "either" is the right answer, but I'm not counting out the use of some mystery units in some of the diagrams too. Sometimes the numbers just seem "wacky".

Take care,
-Peter

[ExpAnonColin]

What I'm looking at here is a piezo buzzer... it says on the measurements that the pins are "2.0" wide, and the device is "39" in diameter...  Surely they don't mean 2.0cm wide for pins, but a 4cm piezo buzzer that produced 110db would be insane-is it my unfamiliarity with piezo's that's getting me off here?

-Colin

[Eric H]

What I'm looking at here is a piezo buzzer... it says on the measurements that the pins are "2.0" wide, and the device is "39" in diameter...  Surely they don't mean 2.0cm wide for pins, but a 4cm piezo buzzer that produced 110db would be insane-is it my unfamiliarity with piezo's that's getting me off here?

-Colin

39mm is a pretty large piezo-buzzer --the ones in smoke-alarms are quite a bit smaller...and loud as hell.

[Peter Snowberg]

39mm is a great size. The size is large enough to get some decent action from it at lower frequencies. As you move away from the resonant frequency, the efficiency goes way down.

While you're messing with the elements, remember that even the slightest bending of the crystal will break it as well as the conductive ink electrode. I've broken more than one.

but a 4cm piezo buzzer that produced 110db would be insane

Pretty cool isn't it? Too bad they're not very loud once you move away from the resonant frequency.

Take care,
-Peter

[ExpAnonColin]

OK, definitely getting that... that's like, purse-sized-110db siren mahem for $4...  Thanks for the breaking tip, I would never have guessed.

-Colin