Choose the correct option for an n-p-n transistor.
Hint:-Transistor is a semiconductor device having three doped regions and two junctions, used to amplify or switch electronic signals and electrical power. An n-p-n type of the transistor is the most commonly used bipolar junction transistor that consists of a p-type semiconductor sandwiched between two n-type semiconductors.
Complete step-by-step solution:- The n-p-n transistor’s base is thin and lightly doped, the emitter is heavily doped and collector is the largest region out of these three with doping level between the doping levels of emitter and base. In the symbol of a transistor, the arrow points hole current which is conventional current. Therefore, the emitter in the n-p-n transistor is represented by an arrow pointing away from the base. It should be noted that the arrow points in the direction of conventional current or hole current even though in the n-p-n transistor, the current is carried by electrons. The n-type emitter is forward-biased by connecting it to a negative terminal of the battery and n-type collector is reverse-biased by connecting it to the positive terminal of the battery. From the above discussion, we can say that the correct option is (C).
Note:- Similarly, in the other type of transistor i.s. p-n-p type of the transistor, the emitter is represented by an arrow pointing towards the base. Thus, the current in the p-n-p transistor is carried by the holes due to the majority carriers being the holes. Also, the working of both the types of the transistor is similar, except that the minority and majority carriers in the two cases are opposite.