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27.12 MHZ Crystal

sleepless

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?
 

rjenkinsgb

Well-Known Member
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.
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120514

[Image from this page: https://electronics.stackexchange.com/questions/290923/generation-of-higher-freq-from-lower-freq-crystal ]
 

unclejed613

Well-Known Member
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.
 

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