I do not understand your question, oscillators CAN be built with either (and many other amplifying components). A few examples are:
Perhaps you meant why it was in some specific circuitthat you don't give any reference to. If this is the case, I cannot answer without a reference to the specific circuit. One possibility for selecting a tube instead of a transistor to implement an oscillator would be that it must deliver higher power and/or voltage than a transistor is capable of.
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.
whatever works at the desired operating frequency
To isolate the bias circuitry of the transistor from the feedback network with RF currents.
before the invention of transistor,thyristor was used instead of transistor but thyristor produces more heat in the circuit and size is more when compared to transistor
With a diode tube you have no control over the current flow and it can only be used as a rectifier, where the triode consist of a control grid, to control the flow of electrons that will reach the anode, this make it possible to use the triode as a amplifier, compared to a transistor the control grid have the same function as the base of the transistor.Advantages?Over tetrodes and pentodes:1. Operation at higher radio frequencies,2. Lower noise figures,3. Simpler circuitry and only one power supply.
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
whatever works at the desired operating frequency
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
a tetrode is used when you need a screen grid tube, but a suppressor grid tube can't be used.OK, but the question was "why use a tetrode instead of a triode?"So, the answer...1. A tetrode has a higher voltage/power gain than a triode.2. A tetrode has less anode-grid feedback capacitance than a triode, and can operate in common-cathode radio frequency circuits without the neutralisation (or other corrective circuitry) that is needed by a triode.
Colpitt oscillator is better than hartley because colpitt produces less phase noise and uses capacitor instead of inductor as used in hartley oscillator which means that area is also saved.
before the invention of transistor,thyristor was used instead of transistor but thyristor produces more heat in the circuit and size is more when compared to transistor
With a diode tube you have no control over the current flow and it can only be used as a rectifier, where the triode consist of a control grid, to control the flow of electrons that will reach the anode, this make it possible to use the triode as a amplifier, compared to a transistor the control grid have the same function as the base of the transistor.Advantages?Over tetrodes and pentodes:1. Operation at higher radio frequencies,2. Lower noise figures,3. Simpler circuitry and only one power supply.
in second generation of computer transistor were used transistor are used instead of vaccum tube are used in first generation high level langauges such as gobsl, fortran are used
a crystal 32.768kHz oscillator.
A Wein Bridge Oscillator is a oscillator which is used for the measurement of Audio Frequency.