How a n-p-n transistor is used as an amplifier. Show with its circuit diagram

The circuit using a n - p - n transistor in common emitter m ode as an amplifier is shown in the figure . In put emitter- base circuit is forward biased with the battery V BB and the output collector-emitter circuit is reversed biased with the battery V CC Hence, the resistance of input is low and that of output is high A low input is applied in the input and a high voltage is obtained across the load resistance R L During the positive half cycle of the input a.c signal, it supports the forward biasing of the emitter base circuit. Due to this, the emitter current increases so that the collector current also increases making the collector less positive (negative e.r.t initial value), therefore the output voltage at the collector varies through a negative half cycle. During the negative half cycle, it opposes the forward biasing of the emitter base circuit, hence the emitter current decreases and thus the collector current decreases consequently the collector voltage V CE Increases and the collector becomes more positive as such the output voltage varies the through the positive half cycle