In semiconductor physics, what is meant by:
(ii) an amplifier
(iii) an oscillator
(i) Rectifier: It is a device which converts alternating current into direct current.
(ii) Amplifier: An amplifier is a device which increases the energy of a weak signal by supplying energy from an external source. An amplifier increases the amplitude of a input signal.
(iii) Oscillator: An oscillator is a device which produces electrical oscillations of adjustable frequency and constant amplitude. An oscillator is basically an amplifier. A part of the output energy is fed back into the L-C circuit to produce sustained oscillations.