whatever works at the desired operating frequency
The oscillator which is blocked by using transformer is called a blocking oscillator. Generally, the primary is given to the base and secondary is given to the collector of the transistor used in the oscillator circuit.
a crystal 32.768kHz oscillator.
To isolate the bias circuitry of the transistor from the feedback network with RF currents.
the Colpitts oscillator , named after the inventor of the circuit , is characterised by the use of Two Capacitors in series which are then connected in parallel across the inductor of the resonant circuit for obtaining the required frequency. The junction of the two capacitors is used for the positive feedback used for generating the oscillations. This circuit is used for High frequency oscillators , mainly due to ease of obtaining required ratio of the two capacitor values as per the circuit design. Also the two capacitors in series reduces their total equivalent value , which is not a problem as in HF circuits as the values and size is comparatively low. For information , a corresponding Low frequency circuit is called a Hartley oscillator , also named after its inventor. This uses a tapped inductor & one capacitor for the resonant circuit, since it is more easier to fabricate large value tapped inductors , than to use two bulky ( since the value of capacitors in series is reduced ) capacitors necessary for the equivalent Colpitts oscillator.
Positive feedback
advantages over what? Colpitts? Mostly the fact that it does not require a choke. A Hartley is more harmonic-rich than a Colpitts, so the main reason it is used lies in its (relative) ease of construction.
The oscillator which is blocked by using transformer is called a blocking oscillator. Generally, the primary is given to the base and secondary is given to the collector of the transistor used in the oscillator circuit.
for high frequency applications(RF oscillator) we use BF 194
a crystal 32.768kHz oscillator.
To isolate the bias circuitry of the transistor from the feedback network with RF currents.
for high frequency applications(RF oscillator) we use BF 194
the Colpitts oscillator , named after the inventor of the circuit , is characterised by the use of Two Capacitors in series which are then connected in parallel across the inductor of the resonant circuit for obtaining the required frequency. The junction of the two capacitors is used for the positive feedback used for generating the oscillations. This circuit is used for High frequency oscillators , mainly due to ease of obtaining required ratio of the two capacitor values as per the circuit design. Also the two capacitors in series reduces their total equivalent value , which is not a problem as in HF circuits as the values and size is comparatively low. For information , a corresponding Low frequency circuit is called a Hartley oscillator , also named after its inventor. This uses a tapped inductor & one capacitor for the resonant circuit, since it is more easier to fabricate large value tapped inductors , than to use two bulky ( since the value of capacitors in series is reduced ) capacitors necessary for the equivalent Colpitts oscillator.
There are many different types of oscillator circuits, the majority of which use positive feedback.
Metal Oxide Semiconductor. Usually used when referring to a specific type of transistor which uses this type of semiconductor material: the Field Effect Transistor (FET).
Positive feedback
The answer depends on the type of transistor, how intensively it is used as well as the manufacturer.
transistor