Describe the use of transistor as an oscillator.

Explanation

An L-C circuit can be used to produce oscillations of desired frequency.
It consists of a tank circuit consisting of inductor L and capacitor C connected in parallel.
The frequency of the tank circuit is given by
`v=(1)/(2pisqrt(LC))`
Due to the resistance of inductive coil, there occurs a small but constant energy loss and oscillations thus produced are damped. To transmit speech or music, we require undamped electromagnetic waves called carrier waves.

To do so an L-C circuit is coupled with transistor in such a way that there is a proper feedback to the L-C circuit at the proper timings so that the energy of L-C circuit remains the same throughout oscillaitons.
When key K is pressed, the collector attains positive potential due to which a weak collector current will start rising in `L_(1)`. The increasing magnetic flux is linked with `L_(1)` and hence with L.