27.12mHz Crystal Oscillator Project.

Thread Starter

TJD

Joined Dec 6, 2015
4
Hi all, I'm trying to make a 27.12mHz Oscillator circuit and, for stability would like to use a crystal. Looking on various component websites I see that such a crystal comes in a VERY small surface mount package. Does anyone know of a larger component size package for Breadboard Prototype/Project PCB type mounting?
 

recklessrog

Joined May 23, 2013
985
Have a look for 27Mhz radio control transmitter crystals. Amazon list a lot, 27.125Mhz is a standard frequency, and if you put a small value trimmer capacitor in your circuit, you should be able to "pull" the xtal frequency to your 27.12.
 

kubeek

Joined Sep 20, 2005
5,661
Those packages aren´t SO small, with a bit of patience you should be able to easilly connect wires to it.
And also I think you mean 27.12 MHz, not mHz.
 

MikeML

Joined Oct 2, 2009
5,444
That frequency is between Chan 13 (27.115) MHz) and Chan 14 (27.125 MHz) in the standard CB band.

I find old CBs, some crystal-controlled, most synthesized, at garage sales for cheap....
 

Thread Starter

TJD

Joined Dec 6, 2015
4
Thanks for all the help. Short of just following an oscillator circuit from a book, does anyone know of any good oscillator tutorials to get me started. I'd rather understand how the circuit works than just build it. And if you haven't worked it out, yes I'm very new at this!
 

BR-549

Joined Sep 22, 2013
4,938
If you want to understand how the oscillator works, I would recommend those military courses.......NEETS I think they call it. There’s a few here real familiar with it. They’ll chime in shortly. Hopefully.

That’s as good a study as any.
 

Thread Starter

TJD

Joined Dec 6, 2015
4
An even frequency in that band is odd. Even R/C, I believe, uses odd frequencies....i.e ending in 5.

Those crystals are cheap, and easy to find. Pull one. As suggested.

Maybe this is what you need. I have no idea what they use it for. Diathermy perhaps?

http://www.microsemi.com/document-portal/doc_view/123626-drf1200-27-12mhz-reference-design-kit
Thanks for this, sounds ideal. The 27.12mHz is (apparently) used for RF Welding of PVC, which is what I need it for. I don't know if a few Hz either way would make too much difference.
 

recklessrog

Joined May 23, 2013
985
Dielectric loss pre heating of plastic pellets for extrusion moulding was done with a very powerful R.F generator at a company I used to work for, I am pretty sure it was not a critical frequency as it was not stabilised. As far as I can recall, it was anywhere from 25-30MHz. All I can remember is that It weighed about 200Lbs and had an enormous Valve that lit up like a light bulb!
 

Thread Starter

TJD

Joined Dec 6, 2015
4
Dielectric loss pre heating of plastic pellets for extrusion moulding was done with a very powerful R.F generator at a company I used to work for, I am pretty sure it was not a critical frequency as it was not stabilised. As far as I can recall, it was anywhere from 25-30MHz. All I can remember is that It weighed about 200Lbs and had an enormous Valve that lit up like a light bulb!
Great - Will keep you posted!!
 
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