Is it a hartely oscillator??

[KevinIV]

The variable capacitor has to be a higher impedance than the series inductor so that the collector voltage is inverted compared to the base voltage. Unless the feedback capacitor and transistor base add to the phase shift, the amplitude is reduced by at least 75%.

[audioguru]

The variable capacitor has to be a higher impedance than the series inductor so that the collector voltage is inverted compared to the base voltage. Unless the feedback capacitor and transistor base add to the phase shift, the amplitude is reduced by at least 75%.

No.
I explained how the center-tapped inductor inverts the signal with 180 degrees phase shift so the transistor provides the other 180 degrees phase shift for it to oscillate.

[Hero999]

No.
I explained how the center-tapped inductor inverts the signal with 180 degrees phase shift so the transistor provides the other 180 degrees phase shift for it to oscillate.

Yes and no doubt he'll ask the same question again and again.