Question

(a) Describe briefly the functions of the three segments of n-p-n transistor.
(b) Draw the circuit arrangment for studying the output characterstics of n-p-n transistor in CE configuration. Explain how the output characterstics is obtained.

Answer 1

(a) A junction transistor is obtained by growing a thin layer of one type semi-conductor in between two thick layers of other similar type semi-conductors.
Three layers and functions
Emitter ( E) : The left hand thick layer of the transistor which is heavily doped and moderate in size is called emitter. If emits majority charge carriers.

Output Characteristics : The variation fo the collector. Current `(I_(c))` with the collector emitter voltage `(V_(CE))` keeping the base current `(I_(b))` constant is called output characteristics.
(i) Baxe (B) : It is a central thick layer of the transistor which is lightly deped. Correlates interaction between emitter and collector.
(iii) Collector ( C) : The right hand hand side thick layer of the transistor which is moderately deped is called collector. It collect the majority charge carriers.