Applications of MOSFET

Introduction
The field of technology is getting advanced day by day in a fast pace, making our
life easier and more efficient. Things are getting smaller, faster, smarter and
ultimately, better than their previous generations. The world of electronics
changed after the invention of transistors. A transistor is a semiconductor that is
used to maintain and regulate the voltage and current level on an electrical circuit.
A MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is a type of
IGFET (Insulated Gate Field Effect Transistor) that is fabricated by the
controlled oxidation of a semiconductor (typically Silicon). It is one of the most
essential components in most of the electronic devices like smartphones, laptops,
power systems etc. that are present in today’s world.
This article presents a relative study of the applications of MOSFETs in different
fields.

MOSFET : an overview
A MOSFET is a special type of transistor that is used to control the flow of
electrical current in circuits. It is a three-terminal device with Source, Drain and
Gate. It works by varying the width of a channel along which charge carriers flow
(electrons or holes). The charge carriers flow into the channel through the source
and leave through the drain. The channel’s width is controlled by the applied
voltage on the gate.

Figure : Basic structure of a MOSFET

MOSFETs are mainly of 2 types –

• N-MOS (Source and Drain are n type, Body is p type)
 • P-MOS (Source and Drain are p type, Body is n type)
A MOSFET can operate in two modes. These are –
Enhancement mode : In this mode, the MOSFET is normally off and a voltage
must be applied to the gate to induce a conductive channel for current flow.
Depletion mode : In this mode, the MOSFET is normally on and applying a
voltage to the gate reduces or depletes the conductive channel which potentially
turns it off.

The versatility of a MOSFET allows it to be used in a wide range of applications

and makes it an important component in shaping modern electrical designs.

Applications of MOSFETs
MOSFETs are being used in many fields of technology making modern
electronics more efficient and reliable. Some are highlighted below :

1. Amplification and signal processing : Because of high electrical impedance

and switching speed, MOSFETs tend to be ideal for signal processing and
amplification. In case of amplification,
• MOSFETs can boost weak electrical signals and make them stronger. This
characteristic is widely used in audio amplifiers. As a result, we get clear,
high-quality sound in automobile sound systems and professional sound
setups.
• MOSFETs can be seen being used in chopper amplifiers and operational
amplifiers. They ensure precise signal control which makes them essential
in audio and communication systems.
 • In case of signal processing, MOSFETs can also serve as analog switches
by routing signals in complex circuits ignoring the noise and distortions.

Figure : MOSFETs as sound amplifiers

2. Switching : Because of having fast and efficient operation, MOSFETs serve a

vital role in digital and switching application processes. In this case,
• MOSFETs are likely to be heavily used in digital logic gates like NAND,
NOR etc. which form the foundation of the modern ICs.
• MOSFETs are seen being used in memory devices because they enable
efficient data storage and retrieval, powering everything from personal
computers to large-scale data centers.
• MOSFETs are also used in voltage regulators that maintain constant level
of voltage across electrical circuits in order to protect sensitive components
and ensure stable performance.

Figure : MOSFET in voltage regulators

3. Power electronics : MOSFETs are very essential in power electronics offering
efficient control and management of electrical power. It can be mentioned that,
• In switch mode power supplies and DC converters, MOSFETs regulate
voltage levels with minimal energy loss which ensures stable operation of
modern devices like phones, PCs and industrial machines.
• MOSFETs are crucial in motor control circuits, enabling precise speed
and torque control in DC motors, electric vehicles and robotics.

Figure : MOSFET in DC converters

4. Automotive applications : MOSFETs are popular in the auto-mobile

industries. It can be seen that,
• MOSFETs play a vital role in electric and hybrid vehicles. They are used
in controlling the power flow between batteries, motors and other
components.
• In regenerative braking systems, MOSFETs are highly used which
improves overall vehicle efficiency.
• In the auto-mobile sound systems, MOSFETs are used to produce high
quality audio output.

Figure : MOSFET in electric vehicles

5. Consumer electronic products : In our everyday products and gadgets,
MOSFETs are highly used. In this case,
• MOSFETs are used for power distribution of a smartphone which ensures
better performance with efficient battery life. PC motherboards contain
MOSFETs that ensure stable power delivery to CPUs and GPUs. TVs
contain MOSFETs in their circuits for energy conversion and controlling
backlighting systems in LED and OLED displays.
• In wireless devices like charging docks and Wi-Fi routers, MOSFETs help
to regulate power for better energy and signal transmission.
• Home appliances like AC, washing machines etc. use MOSFETs for better
energy saving capabilities.

Figure : MOSFET in TV circuit

6. Other specialized fields : Beyond the mentioned fields, MOSFETs can be

seen in some other special fields as well. Like,
• MOSFETs are used in Radio communications as oscillators.
• In aerospace and defense system, MOSFETs are used for critical data
communications.
• MOSFETs convert DC to AC in solar inverters.
• In medical devices, MOSFETs play a crucial role in diagnosis works.
7. Future trends of applications : New materials like SiC and GaN are allowing
MOSFETs with better upgrades. These upgrades can be helpful for e-vehicles,
renewable energy and advanced AI gadgets of the future. Smart future gadgets
are likely to use MOSFETs for better performance.

Figure : SiC and GaN material

Conclusion
In this article, the overall details and applications of MOSFET has been studied.
They play an important role in modern electronics. With newer upgrades and
improvements, MOSFETs will continue to create innovation and thus make the
world of technology smarter, greener, efficient and accessible.

References
1. Teja, R. (2024, September 11). Introduction to MOSFET |
Enhancement, Depletion, Amplifier, Applications. Retrieved from
https://www.electronicshub.org/mosfet/
2. GeeksforGeeks. (2024, April 20). What is MOSFET? Retrieved from
https://www.geeksforgeeks.org/mosfet/
3. Wikipedia. (July 2022). List of MOSFET applications. Retrieved from
https://en.wikipedia.org/wiki/List_of_MOSFET_applications
4. CD-Team. (2024, June 18). What is a MOSFET? It’s Types, Working,
Circuit, and Applications. Retrieved from
https://www.electronicsforu.com/technology-trends/learn-
electronics/mosfet-basics-working-applications
5. What is a MOSFET: Woking and Its Applications. Retrieved from
https://www.elprocus.com/mosfet-as-a-switch-circuit-diagram-free-
circuits/
6. Saravanan. (2023, December 28). Why MOSFET Over BJT. Retrieved
from
https://www.coursehero.com/file/222058511/Why-MOSFET-Over-
BJTdocx/