What are MOSFETs?

A MOSFET, or a Metal Oxide Semiconductor Field Effect Transistor, is a special type of semiconductor, transistor device designed to control the current flow between the source and the drain terminals. It operates much like a switch, and is capable of switching on and off and/or increasing electronic signals. A Q capacitor controls a MOSFET. MOSFETs are usually mounted onto Printed Circuit Boards (PCBs) as integrated circuits (ICs).

Types of MOSFET

Broadly, MOSFETs can be categorised into two types - N channel MOSFETs and P channel MOSFETs, quite similarly to JFETs.

• N-channel MOSFETs: These types of MOSFETs are more popular and possess additional electrons capable of moving around freely. A positive charge needs to be applied to the gate terminal to make a N channel MOSFET work.
• P-channel MOSFETs: These types of MOSFETs remain attached to a positive voltage and have electrons as well as electron holes. The charge applied to the gate terminal needs to be lower than the voltage of the source terminal to make the P channel MOSFETs work. 

Other than these, MOSFETs are available in the market in different varieties of standardised package types. These include DFN, SOIC, DPAK, D2PAK, and TO-220, to name a few.

Applications

MOSFETs have typical applications across the consumer electronics industry. The most common applications of MOSFETs can be found in: 

• Smart devices like smart watches and smart phones
• Digital wristwatches
• Calculators 
• Video games
• Computers
• Telecommunication devices like mobile phones
• Disk storage
• Electric clocks
• HVAC systems like air conditioners or heating systems
• Lighting systems
• Home appliances
• Portable electronic 
• RF energy technology devices