colpitts oscillator circuit

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ymmen

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how to find the range of inductance for which the circuit will function well in following circuit?
 

Talking about an exact solution, you'll derive the circuit loop gain and determine the L range for that the Barkhausen oscillation condition can be fulfilled. Deriving the exact loop gain in a hand calculation is rather complex, even with a circuit simulator it's not really easy.

A more practical approach is to estimate a useful range of LC circuit characteristic impedance √L/C related to the common emitter stage input- and output impedances.

Besides finding a reasonable L value for the given circuit, it should be also checked if the other circuit parameters haven been chosen suitably. How did you derive it?
 


As i have read, in colpitts oscillator if A>C2/C1 the circuit is capable of oscillating at resonant frequency. but how does the change in value of inductor affect this stability criteria?

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this was the frequency response of the circuit, and with the current circuit my inductance value is ranging from 10uH to 1mH. How can I increase this range
 

A larger Henry value creates greater impedance to a given frequency.

If you increase Henry value, then you must reduce capacitor value, if you wish to keep a given frequency. You will have reduced current flow back and forth in the LC loop. This may require re-adjusting other component values.

In general, a greater Henry value is associated with:
* lower frequency
* lesser current flow
* larger voltage swings
 

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