Electronics - Bipolar Junction Transistors (BJT) - Discussion

Here for proper operation is mentioned, that means BJT should work as an amplifier and it means BJT should be in (active region), for this junction between base & emitter i.e., emitter junction is FB and junction between base & collector i.e. collector junction (Jc) is RB. Saying base-emitter voltage FB means 'Vbe' is positive. i.e., it's NPN transistor, so in NPN transistor, the collector is positive and the base is negative to make it RB, so the answer is collector-base junction is to be reverse biased.

It cannot be said base-collector because negative terminal is probed to collector which is to be suffixed first and this rule is obeyed for both PNP and NPN transistor. For PNP transistor (under normal operating conditions) collector- base junction is reverse bias and negative terminal is probed with collector therefore it is to be named first while in NPN transistor positive terminal is probed with collector (which is of N-type) and thus suffixed first.

To drive a transistor in active region We should make CB reverse biased (along with EB forward bias) so that we intending stop the flow of carriers from collector to base that is reverse biasing the collector to base (this is general for both NPN & PNP transistors). For this we make sure that of circuit configuration is in such way that collector at low voltage and base at high voltage in PNP transistor and this will be reverse in NPN transistor.

Collector is used for collecting current or charge from emitter by base so collector-base must be reversed bias or base-collector must be forward bias by which no charge move no current flow from collector to another region.

The most common configuration that we are using now in amplifier application is common emitter and the main purpose of transistor is for amplifiers. So the answer must be collector to emitter right?

In NPN Transistor,

Base - Positive, Emitter- Negative, Collector- Negative

To operate Transistor properly i.e., in active mode

BE junction - forward biased
CB junction - reverse biased

Here, the question refers to pnp bjt transistor, since it is given that the BE is forward biased, then the Base collector should be reversed biased for it to operate properly.

@Neha you are right you brief nicely. But I will say in question not mention which types of region of transistor they are asking that is why friends are confused am I right?

Why not base-collector?

Question asking about the name of the junction, so both C-B and B-C must be right.

Please help me because that Question Came in SSC JE 2015.

As the question does not specify the transistor configuration, answer should be Collector to emitter. Because common purpose of the transistor is for amplification.