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crystal controlled astable oscillator problem

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efron

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Yes, all I need is a 12MHz square wave oscillator using just transistors and crystal, not opamps
 

Tahmid

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efron

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Yes, all I need is a 12MHz square wave oscillator using just transistors and crystal, not opamps

If you could limit the frequency to 10 MHz, Tahmid's proposal in his first or second link is a good and practical approach.

For higher frequencies, I can only suggest to use transistor-based XTAL oscillator with a very high gain at the amplifier stage, so that the output will be seen as a square signal because of the saturation of the transistor.

Would you know how to do that ?
 
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neazoi

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If you could limit the frequency to 10 MHz, Tahmid's proposal in his first or second link is a good and practical approach.

For higher frequencies, I can only suggest to use transistor-based XTAL oscillator with a very high gain at the amplifier stage, so that the output will be seen as a square signal because of the saturation of the transistor.

Would you know how to do that ?

Thank you all for the schematics. Limiting the frequency to 10MHz sould be not much of a problem.
You see I have already tried to build one using inverters made out of transistors but it did not work...
But the original circuit from the author worked using 74HCxx and not 74LSxx and my gates were built using DTL and TTL

I have thought about the limiting amplifier solution you propose and this is of much interest but I cannot find any schematic on the web :( Maybe you could help a bit?
 

efron

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I have thought about the limiting amplifier solution you propose and this is of much interest but I cannot find any schematic on the web :( Maybe you could help a bit?

I will come with a proposal in a couple of days as right now I have no spare time :-(
 

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