Problem in Hartley oscillation circuit using LM324 IC as OP AMP in Proteuss?!

[shirko20]

hi everybody, i have tried so much to oscillate this circuit in Proteus but the Osciloscope shows no output wave shape,where is the problem please help

here is the image of circuit: (i used R6 & C3 as trigger pulse but no oscillation steel)

https://obrazki.elektroda.pl/5378517700_1426110432.jpg

 

[FvM]

There are many reasons why the oscillator can't work:

- wrong operation point for OP
- LC circuit impedance probably too low for OP oscillator
- oscillation frequency too high related to OP gain-bandwidth product

 

[BradtheRad]

The Hartley type has a tapped inductor. One winding influences the other. The windings are connected so that they combine to reinforce the resonant action.

Your schematic has L1 and L2 as separate inductors. To correct your circuit, put a transformer instead of L1 and L2. Experiment with connections so that you get sustained oscillations.

 

[D.A.(Tony)Stewart]

I dont think the Wiki design will work.

The difference is polarity and phase shift and the Hartley drives the tapped inductor and feedback one leg with the non inverting side.

try mine

or this variation driving one leg and feedback tap to + input.
Here I attenuated the input and get both Square and sine wave output.

The problem can be too high Q can over-drive the Op Amp input, So I loaded it down but there are other ways,

 

[FvM]

The Wiki design is in fact a failed oscillator design. But it's different in many details from the circuit in post #1 which has only some "minor" faults.

The post #1 topology has sufficient phase shift to fulfill the oscillation condition. But it must be dimensioned according to OP parameters and the OP correctly biased. Most easily connected to a bipolar supply.

 

[shirko20]

thank you for your answers, dear FvM about your "Most easily connected to a bipolar supply."
The LM324 is a bipolar op amp,
can any one correct this circuit and take a picture, it will help me so much thanks again.

 

[FvM]

Bipolar supply means +/-, e.g. +/-5 or +/-12V.