Question

In BJT, maximum current flows in which of the following?
A. in the emitter
B. in the collector
C. in the base
D. through CB junction

Answer 1

Hint: A three-terminal bipolar junction transistor is a semiconductor component with two p-n junctions that can amplify or magnify a signal. It is a device that is current-controlled. The base, collector, and emitter are the three terminals on a BJT.

Complete step by step solution:
Bipolar junction transistors (BJTs) are current-controlled electrical components primarily used for switching and amplification. The emitter, base, and collector terminals are the three that come with it.

Emitter: When compared to the base and collector, the emitter terminal is the region that is strongly doped. This is because the emitter's job is to use the base to give charge carriers to the collector. The emitter is larger than the base but smaller than the collector.

Base: The base region is much smaller than both the emitter and the collector in terms of area. The base is always kept small to prevent charge carriers from recombining in the base region and to ensure that they are directed into the collector region when they enter from the emitter. For the same reason as earlier, the doping intensity of the base is likewise lower than that of the emitter and collector.

Collector: Because all the charge carriers flowing from the emitter recombine at the base and generate heat in the process, the collector terminal is moderately doped, and the collector region is slightly larger than the emitter region. As a result, the collector terminal must be sufficient enough to disperse the heat and prevent the device from overheating.

A signal of moderate amplitude applied to the transistor's base is available at the collector in amplified form. This is the amplification that the BJT offers. Keep in mind that the amplification procedure does require an external source of DC power supply. The base, collector, and emitter of a BJT are three doped semiconductor regions that are separated by two p-n junctions.

The two varieties of bipolar transistors that are produced are PNP and NPN, and they can be found as individual components, usually in huge quantities. Current amplification is the primary purpose or use of this kind of transistor. They can therefore be utilised as switches or amplifiers. They have a wide range of uses in electronics, including industrial control, televisions, radio transmitters, and mobile phones.

A bipolar junction transistor has three functional areas:
Active region: The region in which transistors serve as amplifiers.
Saturation region: When the transistor is completely on and acting as a switch, and the collector current equals the saturation current.
Cut-off region: The area where the transistor is entirely off and the collector current is zero. Because compared to the collector and base terminals, the emitter terminal has the largest area. Therefore, the emitter terminal experienced the greatest current flow.

Therefore, the emitter in a BJT has the highest current flow. Hence, option A is the correct answer.

Note: A transistor's collection supply voltage has a maximum value because if the collector current is increased quickly, there is a danger that the transistor will become damaged. The voltage in the collector needs to have a maximum limit to prevent this.