On Dec 13, 2:16*pm, Fred McKenzie wrote:
In article
,
*Stuart Longland VK4MSL wrote:

Out of curiosity, what's the difference between the "microprocessor"
type crystals and other crystals? *Is it just frequency stability or
is there something more fundamental?

Stuart-

Michael's explanation brought back memories of my teenage years and
home-brew crystal controlled rigs.

A shorter answer is that a microprocessor crystal frequency may not be
critical while a radio crystal frequency may be.

It would be critical if you needed your transmitter to be on an exact
frequency. *In your computer, it wouldn't matter much because no one is
listening! *The only time it would matter is if the crystal frequency is
used to keep the computer's clock accurate.

Hi Michael & Fred,

Yep… economies of scale, I can grasp that. So I'm guessing the main
difference is that one is tuned to a frequency that's more suited to
RF applications (e.g. maybe 455kHz) whereas microcontrollers will be
whatever's convenient for the microcontroller in use.

I was thinking maybe the microcontrollers were somehow less accurate
with the frequency. Of course the fact that they are mass produced
would make them cheaper, but I thought maybe they had taken shortcuts
since microcontrollers are less critical. (For timing purposes, a lot
use a 32.768kHz crystal.)

Thanks for the informative post however. Guess I'm spoiled having
never lived through this earlier time. ;-)

Regards,
Stuart Longland