On Mon, 27 Nov 2006 18:28:24 GMT, "Farce Milverk"
wrote:


"John Fields" wrote in message
.. .
On Mon, 27 Nov 2006 14:54:36 GMT, Ross Herbert
wrote:


What John means is that the 4 pin device you have is an active
oscillator while the 2 pin device is simply a crystal which requires
other active components to get it to oscillate. The 4 pin oscillators
are commonly used to produce clock signals for IC devices. 2 of its
pins are simply to provide + and - power for the internal oscillator
which uses a crystal to set the frequency. The 2 pin crystal doesn't
have the oscillator part so you need to provide it.

---
Right.

Thanks!


--
JF

Great explanation thanks. I have one more question:

Does the 2 pin have a Pin 1 identifier?
Or is this a component that doesn't care?

---
It's a don't care.
---

I see XTAL and EXTAL in the schematic, but don't understand what this means?

If it's for a 4 pin oscillator, that will be a pin which is used to
Enable or disable the oscillator. It could be that either a low or
a high will enable the oscillator, so you can either try it and find
out or go to the manufacturer's website and get the data sheet for
the oscillator.


--
JF