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27.12 MHZ Crystal


New Member
Helo All how to generate a 27.12 Mhz sine wave from a xtal oscillitor .I have to design this Using only 3 volts battery as i have to use this to design a small prototype of threaphy device for healing and pain relief. .Does anyone have any idea?


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Most Helpful Member
A simple colpitts oscillator and a single transistor buffer should give a reasonable sine wave, IF the crystal is cut at that fundamental frequency.
It may be an overtone type, that requires a tuned oscillator.

This is a basic colpitts crystal osc.
You would have to reduce the bias resistor value for 3V operation:

This is a third overtone circuit for 30MHz, which should be OK for 27MHz as well with minor adjustments, though again resistor values would need adjusting for 3V
I'd use a trimcap for C1, either 47pF or 22pF with 10pF in parallel.

[Image from this page: https://electronics.stackexchange.c...ration-of-higher-freq-from-lower-freq-crystal ]


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Most Helpful Member
threaphy device for healing and pain relief.
diathermy? i thought those machines ran a bit of wattage, as well as being restricted to the ISM bands.


New Member
There are different chrystals for given application. The Colpitts shown should fill your bill.
Now just the oscillator is not going to produce enough power for your job. a gain stage would be needed to provide that as many diathermy devices get up to a few watts output.

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