Presentation of transistor

Good presentation for university or college students ....

1. Presented by: Md . Sohag Em@il : [email protected] Daffodil international University

2. Transistor Definition Transistor is an electronic device made of three layers of semiconductor material that can act as an insulator and a conductor. The three layered transistor is also known as the bipolar junction transistor.

3. Let we know about this topics. 1.Evolution of transistor   2.Importance of transistor   3.Definition & transistor types   4.Transistor symbol & operation   5.Advantages of transistor 6.Latest in transistor technology

4. History of transistors In 1906, an American inventor and physicist, Lee De Forest, made the vacuum tube triode or audion as he called it. Used in radios Used in early computers

5. The first transistor In 1947, John Bardeen and Walter Brattain deviced - the first " point contact " transistor.

6. Moore’s Law It’s an observation made by Gordon E. Moore, in which he predicted that the number of transistors, inside an Integrated Circuit, could be doubled every 24 months. At the density that also minimized the cost of a transistor.

7. Basic construction

8. Regions of a transistor A transistor has three regions namely, Emitter- heavily doped Base- lightly doped Collector- moderately doped

9. Transistor symbols Transistor symbols

10. Transistor operation force – voltage/current water flow – current - amplification

11. Transistor biasing The base-emitter (BE) junction is forward biased The base-collector (BC) junction is reverse biased . I E =I B +I C

12. Types of transistor BJT - Bipolar Junction Transistor UJT- Unipolar Junction Transistor FET - Field Effect Transistor MOS - Metal Oxide Semiconductor

13.   The bipolar junction transistor(BJT) A  bipolar junction transistor  ( bipolar transistor  or  BJT ) is a type of transistor that uses both electron and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. For their operation, BJTs use two junctions between two  semiconductor types , n-type and p-type. BJTs are manufactured in two types, NPN and PNP, and are available as individual components, or fabricated in integrated circuits, often in large numbers. The basic function of a BJT is to amplify current. This allows BJTs to be used as amplifiers or switches, giving them wide applicability in electronic equipment, including, computers, televisions, mobile phones, audio amplifiers, industrial control, and radio transmitters.

14. Bipolar Junction Transistors (BJT’s) The term bipolar refers to the use of both holes and electrons as charge carriers in the transistor structure There are two types of BJTs, the NPN and PNP

15. Operating regions of BJT Cut off region Linear region Saturation region

16. The Unijunction Transistor(UJT) The Unijunction Transistor or UJT for short, is another solid state three terminal device that can be used in gate pulse, timing circuits and trigger generator applications to switch and control either thyristors and triacs for AC power control type applications. Like diodes, unijunction transistors are constructed from separate P-type and N-type semiconductor materials forming a single (hence its name Uni -Junction) PN-junction within the main conducting N-type channel of the device.

17. The  field-effect transistor  ( FET ) The  field-effect transistor  ( FET ) is a transistor that uses an electric field to control the shape and hence the electrical conductivity of a channel of one type of charge carrier in asemiconductor  material. FETs are also known as  unipolar transistors  as they involve single-carrier-type operation. The FET has several forms, but all have high inputimpedance . While the conductivity of a non-FET transistor is regulated by the input current (the emitter to base current) and so has a low input impedance, a FET's conductivity is regulated by a voltage applied to a terminal (the gate) which is insulated from the device. The applied gate voltage imposes an electric field into the device, which in turn attracts or repels charge carriers to or from the region between a source terminal and a drain terminal. The density of charge carriers in turn influences the conductivity between the source and drain.

18. Metal Oxide Semiconductor(MOS) The  metal – oxide – semiconductor  field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of transistor used for amplifying or switching electronic signals. Short for  Metal Oxide Semiconductor ,  MOS  is a method of creating transistors. MOS consists of three layers, a metal conductor, insulating silicon layer, and a semiconductor silicon layer.

19. Transistor applications Transistor as a switch When used as an electronic switch, the transistor is normally operated alternately in cut-off and saturation regions.

20. Transistor as amplifier Due to the small changes in base current the collector current will mimic the input with greater amplitude

21. Transistor as a Switch Transistors are commonly used in digital circuits as electronic switches which can be either in an "on" or "off" state, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates. Important parameters for this application include the current switched, the voltage handled, and the switching speed, characterised by the rise and fall times.

22. Future of Transistors Molecular electronics Carbon nanotube transistors Nano inspiration wire transistors Quantum computing CMOS devices will add functionality to CMOS non-volatile memory, opto -electronics, sensing…. CMOS technology will address new markets macroelectronics , bio-medical devices, … Biology may provide for new technologies bottom-up assembly, human intelligence

23. What’s new in transistor technology? 3D Transistor made using Tri-Gate transistors on its 22nm logic technology. Advantage of Tri-Gate Transistors · More than 50% power reduction at constant performance. ·37% performance increase at low voltage ·Improved performance and efficiency.

24. Thanks to all belong with us.