27.145MHz Crystal Oscillator

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?

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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

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Reply to
Steven Cooke
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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.

Reply to
Bruce Varley

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

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Reply to
Steven Cooke

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