27.145MHz Crystal Oscillator

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I want to study how a 27.145MHz crystal controlled Oscillator/Transmitter
from a radio controlled toy works. I think that the input is at the emitter
and output is at the collector. The emitter voltage appears to be out of
phase from the collector. What is the best way of preceeding with my course
of study?

[best viewed in courier font]

V+ ---+ 6VDC    **
        |        | E *
        o        | B  * ED1702L  (Philips 1702L)
         /       | C *
        o         **
        |
        +-----+--[L1]--+------+-----+-------+
        |     |        |      |     |       |
        |   [10K]   [Xtal]    |   [30pF]  [100pF]
        |     |        |     /c     |       |
      [10nF]  +--------+----|       |       +-----[L2]---Antenna
        |     |              \e     |       |
        |     |               |     |       |
        |     |               +-----+       |
        |     |                     |       |
        |   [5K1]                [100R]   [50pF]
        |     |                     |       |
  Gnd---+-----+---------------------+-------+

L1 is 2.56 microHenrys. L2 is a set of windings to decrease the size of the
antenna 24.75 windings 8mm diameter 4.5mm length. Xtal is set at 27.145MHz

Thankyou for your response.

Steven Cooke

http://www.youtube.com/watch?v=BSqDVACew3g




http://www.youtube.com/cookesteven30/




Re: 27.145MHz Crystal Oscillator



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http://www.youtube.com/cookesteven30
/
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What do you mean by 'study'? If that's really your question, ask Google and
it'll tell you, probably including suggesting you might do a course, or read
books, or consult the web.

Maybe what you're really saying is you'd like to understand how it works.
Search crystal oscillators and look for a circuit that's similar to the one
you have, many websites have good technical descriptions. Long, long time
since I built a XO with a discrete, IIRC it looks like a Pierce oscillator.
In fact, many of the configurations are essentially very similar, the
explanation for one can be applied with a bit of adaptation to others.



Re: 27.145MHz Crystal Oscillator




Quoted text here. Click to load it

Thankyou for your response.

The internet and textbooks (that I have read)do not hold the answer. One can
spend the rest of their life searching through books without having a
detailed understanding (and I have spent about 2 months). I can connect a
similar circuit and it might work or it might not. I suspect that this is
how the world works (trial and error). People do not learn how to analyse
anymore, rather they copy other's work. I suppose I should just admit defeat
and pretend that I understand along with everyone else. I have taken an
advanced diploma in electronics, but that doesn't mean that I understand
anything other than parts of the biasing arrangement. At the time I was
taking the course I didn't have this specific example in mind so I did not
ask pointedly about it. In my experience asking lecturers about something is
usually hit and miss. One can walk away without an understanding in such
cases also.

In summary, I am disappointed that there isn't an easy answer.

Steven Cooke

http://www.youtube.com/watch?v=BSqDVACew3g




http://www.youtube.com/cookesteven30/




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