Transistor

 Transistor :

                    Transistor is a electronic device which is used for switching and amplification in a circuit.

Symbol :-

                  

Circuit Diagram :

                             Figure : Switching

                    Figure : Amplification

Types of transistors :-

1) BJT (Bi polar junction transistor)

   a) NPN transistor.

   b) PNP transistor.

2) FET (field effect transistor)

   a) Junction FET.

   b) MOSFET.

Number or Coding system :-

- Europe manufacturing code.

- USA manufacturing code.

- JAPAN manufacturing code.

Pro electron numbering scheme (Europe)

Find coding use middle row -

 First letter -

 • A = Germanium

 • B = Silicon

 • C = Gallium Arsenide

 • R = Compound material

 Second letter -

JEDEC  coding system (USA)

To find code use first one row {2N}

First letter -

• 1 = Diode

• 2 = Bipolar transistor or single gate field               effect transistor.

• 3 = Dual gate field effect transistor.

Second letter -

 Second letter = N ( always)

JIS semiconductor device numbering scheme (Japan)

To find code use first one row {1SN}

First letter -

• 1 = Diode

• 2 = Bipolar transistor or single gate field               effect transistor.

• 3 = Dual gate field effect transistor.

Second and third letter -

Application and Uses :-

BJT ( Bi polar junction transistor)

* It is use for smaller current

* It is use low power circuit.

* It is use in current controlled device.

* It is use in low noise level.

MOSFET ( Metal oxide semiconductor FET)

* It is use in Voltage regulation.

* It is use for large current.

* It is use for high power circuit.

* It is use in Voltage controlled device.

* It is use in high noise level.

Example :

If we have a 12 volt battery and 3 volt LED then we use MOSFET (LM7805) between the battery and LED in the circuit.

Circuit Diagram :

MOSFET size :-

* LM78xx

* LM7803

* LM7806

* LM7808

* LM7812

* LM7824 till 

* LM7848.

Note : Value depends on output device                      voltage.