RF_ freak
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RFICDUDE wrote on Jul 16th, 2012, 5:25pm:From your post it sounds like you are looking for a practical guide to VCO operation without a lot of detailed theory.
This is an open ended question that makes it very difficult for the members to know how to respond.
Can you describe the constraints you are trying to work within? Thanks for the reply!
Yes, exactly, so practical that I can replace the original transistor to any ft similar transistor and still get the circuit to work as well.
In this example I copied the design and I used hypothetical all variable components at the outset . then I kept adjusting this potentiometer, that capacitor ,and so..etc till I got the final result.
This means I have to sit for hours on end in front of the simulator, besides sometimes I leave the circuit working after successful design and when I come the next day to add or simply look at it I find that it doesn't work!!!
Even if it does I don't know how reliable and sound in practice!
Is there a better way using own drawn schematic, a calculator and pen to design a 100% working VCO?
To put it simply: how can I set the transistor out to work as an oscillator? The hartley, colpitts etc. networks are left to me.
How can I bias another transistor to amplify the VCO's signal?
Two stages!
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