For a transistor,the current ratio $\beta_{dc}$ is defined as the ratio of:

$A$ transistor oscillator is $(i)$ an amplifier with positive feedback,$(ii)$ an amplifier with reduced gain,$(iii)$ the one in which $dc$ supply energy is converted into an output energy. Then

$A$ transistor has a voltage gain '$A$'. If a fraction '$\beta$' of its output is fed back to the input of the transistor,then the transistor becomes an oscillator when:

In the following common emitter configuration, an $NPN$ transistor with current gain $\beta = 100$ is used. The output voltage of the amplifier will be

In a common base amplifier,the phase difference between the input signal voltage and the output voltage is

When a transistor is used as an amplifier in common emitter configuration,which of the following statements are correct?
$(1)$ The base-emitter junction is forward-biased.
$(2)$ The base-emitter junction is reverse-biased.
$(3)$ The input signal is connected in series with the biasing voltage to the base-emitter junction.
$(4)$ The input signal is connected in series with the biasing voltage to the base-collector junction.