N type-sc

n type

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2. SUBMITTED TO : Name : Mr . S.M.Safayet Ullah Designation : Lecturer Department : Department of Natural Sciences Faculty : Faculty of Science and Information Technology E-mail : [email protected] Cell-Phone : [phone]

3. Nadim Ahmed ----152-15-5869 Nazmul Islam------152-15-5652 Mehedi Hassan----161-15-7667 Arafat Rahman----152-15-5983 Taijul Islam---------152-15-5613 SUBMITTED BY

4. TOPICS :--- ‘‘ n- typese , Reverse Biasing,Bridge,Zener Diode ”

5. N type SC

6. When a small amount of pentavalent impurity added to a pure SC, It’s known as n type SC When any pantavalent element such as Phosphorous, Arsenic or Antimony is added to the intrinsic Semiconductor , four electrons are involved in covalent bonding with four neighboring pure Semiconductor atoms. The fifth electron is weakly bound to the parent atom. And even for lesser thermal energy it is released Leaving the parent atom positively ionized. N - type Semiconductors

7. N-type Semiconductor Si Si Si P Si Free electron Impure atom (Donor)

8. Reverse Biasing

9. When an external voltage is applied to the P-N junction making the P side negative with respect to the N side the diode is said to be Reverse Biased. The barrier potential difference increases. The depletion band widens preventing the movement of majority carriers across the junction. A Reverse Bias diode has a very high resistance. Reverse Bias P-N Junction

10. Reverse biasing

11. Full wave Bridge

12. Full Wave Bridge Rectifier In Full Wave Bridge Rectifier , an ordinary transformer is used in place of a center tapped transformer. The circuit forms a bridge connecting the four diodes D 1 , D 2, D 3 , and D 4 . The circuit diagram of Full Wave Bridge Rectifier is shown below

13. The diodes D 1 and D 3 are forward biased and the diodes D 2 and D 4 is reversed biased. Therefore, diode D 1 and D 3 conduct and diode D 2 and D 4 does not conduct. The current ( i ) flows through diode D 1 , load resistor R L (from M to L), diode D 3 and the transformer secondary. The waveform of the full wave bridge

14. During the negative half cycle, the end A becomes negative and end B positive as shown in the figure below.

15. Operation of Full Wave Bridge Rectifier When an AC supply is switched ON, the alternating voltage V in appears across the terminals AB of the secondary winding of the transformer which needs rectification. During the positive half cycle of the secondary voltage, the end A becomes positive, and end B becomes negative as shown in the figure below.

16. Advantages of Full Wave Bridge Rectifier The center tap transformer is eliminated. The output is double to that of the center tapped full wave rectifier for the same secondary voltage. The peak inverse voltage across each diode is one-half of the center tap circuit of the diode. Disadvantages of Full Wave Bridge Rectifier It needs four diodes. The circuit is not suitable when a small voltage is required to be rectified. It is because, in this case, the two diodes are connected in series and offer double voltage drop due to their internal resistance .

17. Zener Diode 26 October 2016 19

18. What is Diode? A diode is a semiconductor device with two terminals, typically allowing the flow of current in one direction only.

19. Identification A properly doped crystal diode Has sharp breakdown voltage An electronic component which can be used to make a very simple voltage regulator circuit 26 October 2016 21

20. Different types of Diode

21. Characteristics . . A Zener diode is always reverse connected When forward biased, its characteristics are just like of ordinary diode It has sharp breakdown voltage, called Zener voltage 26 October 2016 23

22. Working of Zener A zener diode is much like a normal diode. The exception being is that it is placed in the circuit in reverse bias and operates in reverse breakdown. This typical characteristic curve illustrates the operating range for a zener . Note that it’s forward characteristics are just like a normal diode.

23. Table for the zener diode

24. FINISHED 26 October 2016 27

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