Transistor

• A Transistor is a device that regulates current or voltage flow and acts a switch.
• Made of semi conductor called Silicon.
• Transistors are the widely used in electronic devices.

Transistors works in two formats:

Switch:

• Used to ON or OFF electronic devices.
• Speed of electronic devices depend on the ON/OFF speed of transistors.

Amplifier:

•  To amplify the lower current to higher current.
• Also to amplify the weak signals to strong signals. 

Types of Transistors:

BJT(Bipolar Junction Transistor):

• Bipolar Junction Transistor is used in electronic equipment like computers, television mobile, phones etc.
• Used  to control the current.
• Contains emitter, collector and drain
• BJT are two types
• P-N-P Transistor
• N-P-N Transistor

P-N-P Transistors:

• N- Type semiconductor is sandwiched between the two P-Type Semiconductors.
• In this majority carriers are holes.
• Power flow from the emitter to collector.

N-P-N Transistors:

• P-Type semiconductor is sandwiched between the two N-Type Semiconductors.
• In this majority carriers are electrons.
• Power flow from the collector to emitter.

 Field Effect Transistor:

• Used to control voltage.
• Contains Drain, Source, Gate.
• FET are two types:
• JFET
• MOSFET

JFET(Junction Gate Field Effect Transistor):

         MOSFET(Metal Oxide Semiconductor Field Effect Transistor):