N type-sc
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This document provides information about an individual, their contact details, and discusses several topics in electronics including n-type semiconductors, reverse biasing of PN junctions, full wave bridge rectifiers, and Zener diodes. It describes how doping a semiconductor with an impurity creates an n-type material with free electrons. It explains reverse biasing prevents carrier movement across a PN junction. It outlines the operation of a full wave bridge rectifier using four diodes to produce full-wave rectification. And it discusses the characteristics and usage of Zener diodes as voltage regulators.
N type-sc
- 2. Name : Mr. S.M.Safayet Ullah Designation : Lecturer Department : Department of Natural Sciences Faculty : Faculty of Science and Information Technology E-mail : safayet.ns@diu.edu.bd Cell-Phone : 01717497562
- 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 SiPSi Free electron Impure atom (Donor)
- 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 D1, D2, D3, and D4. The circuit diagram of Full Wave Bridge Rectifier is shown below
- 14. THE DIODES D1 AND D3 ARE FORWARD BIASED AND THE DIODES D2 AND D4 IS REVERSED BIASED. THEREFORE, DIODE D1 AND D3 CONDUCT AND DIODE D2 AND D4 DOES NOT CONDUCT. THE CURRENT (I) FLOWS THROUGH DIODE D1, LOAD RESISTOR RL (FROM M TO L), DIODE D3 AND THE TRANSFORMER SECONDARY. THE WAVEFORM OF THE FULL WAVE BRIDGE
- 15. DURING THE NEGATIVE HALF CYCLE, THE END A BECOMES NEGATIVE AND END B POSITIVE AS SHOWN IN THE FIGURE BELOW.
- 16. OPERATION OF FULL WAVE BRIDGE RECTIFIER • When an AC supply is switched ON, the alternating voltage Vin 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.
- 18. • 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.
- 19. ZENER DIODE 26 October 2016 19
- 20. WHAT IS DIODE? • A diode is a semiconductor device with two terminals, typically allowing the flow of current in one direction only.
- 21. 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 2 1
- 22. DIFFERENT TYPES OF DIODE
- 23. 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
- 24. 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.
- 26. TABLE FOR THE ZENER DIODE
- 27. FINISHED 26 October 2016 27