Building a Colpitts
Building a Colpitts
(OP)
Hey guys, when it comes to EE I am the epitome of a novice. In fact, I picked myself up a experiment lab from Radioshack the other day to learn some basics. Unfortunately the superiors at work need me to develop a colpitts oscillator that oscillates at 13.46MHz. I was wondering if anyone had any pointers. I'm most confused about which components are necessary to acheive this result.
Thanks in advance.
Thanks in advance.





RE: Building a Colpitts
ARRL handbook will go into detail. Available from any library.
Computer guys (confuser) guys designing a colpitts oscillators. Scary stuff! Hope that Fox Charlie Charlie will not get involved with this!
RE: Building a Colpitts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
http://www.google.com/search?q=colpitts+oscillator
RE: Building a Colpitts
Unfortunately, considering how most physicist feel about the theory of over unity and how it plays into our current understanding of the science, he refuses to invest in seasoned veterans. Furthermore, I doubt he wants to employ an EE for the sake of building one oscillator.
So now I have been burdened with the task of building it, lol. How fortunate (sarcasm).
RE: Building a Colpitts
RE: Building a Colpitts
But why a Colpitts? You've identified effectively 100 ppm accuracy, which would take some doing with any analog approach.
TTFN
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RE: Building a Colpitts
RE: Building a Colpitts
RE: Building a Colpitts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
I'm off to borders to pick up an ARRL handbook for further reference. Thanks for the help guys.
RE: Building a Colpitts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
I obviously don't know all of your requirements, but it is not likely that you want an LC-based oscillator.
RE: Building a Colpitts
VE1BLL, is that so? My understanding of all Colpitts oscillators is that a few of their components' values are frequency dependant (especially the capictors). Then again, I know the least bit about electronics. But that's what I gathered from Wiki.
In either case, I'll try to work out the equation featured on Wiki and see what I come up with. Overwhelming still, It's been years since I've touched Mathematics. I appreciate all the help.
RE: Building a Colpitts
RE: Building a Colpitts
RE: Building a Colpitts
Ironically, he actually owns a few books on Physics. And he understands the complications that are present when taking the fundamental laws of thermodynamics into consideration. But along with Tesla, hundreds of experimentors who have made positive claims of small scale success, and the mysterious Steven Marks, my boss is quite the believer of free energy.
I guess I can't knock him--considering that some of our greatest revolutions were sparked by radical, non-traditional concepts. But as stated before, I'm just a pair of hands looking forward to pay-day Fridays.
RE: Building a Colpitts
Save your money as your boss's will surely run out eventually. Or he'll land in prison for trying to sell some over-unity crap to some gullible mark.
Does sound like you have an interesting job though.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Building a Colpitts
My suggestion, then, would be put down the soldering iron and start searching for another job... your current one is bound to run out of money in short order (assuming the company is based on these over-unity type schemes).
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
Our revenue comes in from the other businesses he owns as well as a few of the patents he holds. For the obvious sensitivity issues of his projects, I'll spare throwing his name around--but rest assured, funding is not of major concern to him.
I really don't mean to spark debate of any sort. Perhaps he is nothing more than some looney, wealthy fool. Nonetheless, I find my work with him to be rather interesting and fruitful noless.
All the help is appreciated. And should anyone truly be interested in the OU debate, I'm definitely no legitimate candidate for or against the argument. But head over to overunity.com. There's some pretty interesting stuff going on in those forums.
Thanks again.
RE: Building a Colpitts
Colpitts: do a search for "dead bug construction" - crude but stable.
Cheers
Harry
(G4NTK in another life!)
RE: Building a Colpitts
Be aware of those DIY sites with RF bugs and spy microphones, often written by non EEs (tech geeks, amateurs, etc.)
Good Luck!
Gonzalo
RE: Building a Colpitts
RE: Building a Colpitts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
Continuing this thread. Hint. Get the boss to pay for the ARRL handbook. When it comes, put YOUR name on it in big bold letters across the top (where all the pages are). When you leave, due to new job, financial problems, whatever, take the book with you!
Cheers,
Rich S.
RE: Building a Colpitts
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Building a Colpitts
RE: Building a Colpitts
But do not tell them to use a crystal. That is not Colpitts any more.
I can not understand why the Colpitts is the only oscillator configuration deemed suitable. There are dozens of other topologies. Could it be that the positive feedback obtained in the Colpitts oscillator reminds some creative souls about over-unity? Which it is, voltage-wise, but not power-wise. Then, why wouldn't a Hartley be just as good? It also has over-unity feedback.
Also, by using a tunable ciecuit (lika a Colpitts) they may be able to find that sweet spot somewhere between 13.46 and 13.56 where the pot of gold resides.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Building a Colpitts
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Building a Colpitts
What is a Colpitts-like xtal oscillator supposed to be called?
RE: Building a Colpitts
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Building a Colpitts
Regards,
Gonzalo
RE: Building a Colpitts
Such a name fails to provide much info on the architecture. It would be like calling an oscillator an 'LC Oscillator' - perhaps accurate but unenlightening.
My ARRL handbook (1989, p. 10-1) shows four xtal oscillators in Figure 1: Pierce, Colpitts, Harmonic, and Overtone. The (xtal) Colpitts has a 10k resistor and two capacitors (47 & 100pF) in series across the xtal, and the feedback is tapped into their junction. Given the difficulty of tapping into the middle of a xtal, perhaps this explains the nomenclature discrepancy.
Cheers.
RE: Building a Colpitts
So, which one should give name to such a circuit? Not that it matters much.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Building a Colpitts
In my grandfather's old (circa 48) ARRL hand book they mention and build a VFXCO (variable frequency crystal oscillator). Using the old FT243 (????) cases (the ones with the three machine screws in them and the "thick" metal plate. Popular from WWII era stuff), they drilled and tapped a 4-40 screw in it and mounted a knob on the outside of the screw. This variable pressure changed the frequency of the crystal up to 10KHz or so.
One could use that for finding the "sweet spot".
They also had an article on "hand lapping" the crystal to move the frequency of surplus crystals UP. Included, if I remember correctly was to lap a slight angle on one corner of the crystal to get it to "ring" better.
Cheers,
Rich S.