What is the purpose of the base region in an NPN transistor?
To control the number of electrons passing from emitter to collector
In an NPN transistor the emitter injects electrons, the collector gathers them, and the thin, lightly doped base sits between the two.
The small current fed into the base sets the width of the base–emitter depletion region, and thereby governs how many of the emitter’s electrons cross the base to reach the collector.
This is the transistor’s control action: a small base current regulates a much larger collector current, which is what makes amplification and switching possible.
The base does not itself generate the electrons (the emitter does), it is not the main current path (that is emitter-to-collector), and its function is control, not heat dissipation.
Hence, the answer is to control the number of electrons passing from emitter to collector.
Identify the component shown in the image below:

The emitter current of a transistor is 1 mA. If 1% of the emitted current carriers are lost in the base recombination, what is the value β? Identify from the given options.
Heat sink of a power transistor can be used for:
In case of an AC input signal in CE Transistor Load line can be given by a plot of
How does the construction of a MOSFET help to achieve high input impedance?
While diagnosing an NPN BJT in a SOT-23 package, your multimeter positive probe (+) is locked on the Base (Pin 1). Measuring to Pin 3 reads 0.6 V, while measuring to Pin 2 reads 0.68 V. Which pin is the Emitter?
Which type of charge carriers mainly control current in a Field Effect Transistor (FET)?
Why are transistors preferred over mechanical switches for rapid switching operations?
In the output characteristics of a common-emitter configuration, a family of curves is obtained by varying VCE while keeping which quantity fixed? (Symbols have their usual meaning.)
The common-emitter (CE) configuration of a transistor is most widely used as a/an:
A transistor has ______ PN junctions
Which of the following is not true for a BJT?
A transistor amplifier with proper biasing has the following measured parameters:
Input resistance = 1 kΩ, Output resistance = 10 kΩ, Current gain = 90.
Identity the biasing configuration.
The change of output wave shape from the input wave shape of an amplifier is known as
Identify the component shown in the image below:
