BFF1303: ELECTRICAL / ELECTRONICS ENGINEERING. Analog Electronics: Rectifier

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1 BFF1303: EECTCA / EECTONCS ENGNEENG Analog Electronics: ectifier smail Mohd Khairuddin, ulkifil Md Yusof Faculty of Manufacturing Engineering Universiti Malaysia Pahang

2 Semiconductor Diodes & Circuits BFF1303 EECTCA/EECTONCS ENGNEENG Contents: Outcomes ectifier Circuit ener Diode Faculty of Manufacturing Universiti Malaysia Pahang Kampus Pekan, Pahang Darul Makmur Tel: Fax: BFF1303 Electrical/Electronic Engineering 2 2

design simple voltageregulator circuits.

3 Understand the diode characteristics and its model earn the types of diodes earn the series and parallel operation of diodes Analyze and design simple voltageregulator circuits. Understand various rectifiers and waveshaping circuits BFF1303 Electrical/Electronic Engineering 3 3

4 Convert AC power into DC power. The basis for power supply and battery charging. For signal processing such as demodulation of signal radio. For precision control of an AC voltage to DC in an electronic voltmeter. BFF1303 Electrical/Electronic Engineering 4 4

5 Half-Wave ectifier Over 1 full cycle, the average value of areas (voltage) is zero. The output waveform, v o that generated by the circuit will give an average value that will be use in AC to DC conversion. The power and current rating are typically much higher than those of diode employed in other applications. BFF1303 Electrical/Electronic Engineering 5 5

6 Half-Wave ectifier The DC output voltage is m, where m = the peak AC voltage. BFF1303 Electrical/Electronic Engineering 6 6

7 P (P) Because the diode is only forward biased for one-half of the AC cycle, it is also reverse biased for one-half cycle. t is important that the reverse breakdown voltage rating of the diode be high enough to withstand the peak, reverse-biasing AC voltage. P P m BFF1303 Electrical/Electronic Engineering 7 7

8 Full-Wave ectifier The rectification process can be improved by using a full-wave rectifier circuit. Full-wave rectification produces a greater DC output: Half-wave: dc = m Full-wave: dc = m BFF1303 Electrical/Electronic Engineering 8 8

9 Full-Wave ectifier (Bridge Network) Four diodes are connected in a bridge configuration BFF1303 Electrical/Electronic Engineering 9 9

10 Full-Wave ectifier (Center-Tapped Transformer) BFF1303 Electrical/Electronic Engineering 10 10

318 m DC = 0.636 m DC = 0.636 m DC = 0.318 m 0.7 DC = 0.636 m 2(0.

11 Summary of ectifier Circuit ectifier deal DC ealistic DC Half Wave ectifier Bridge ectifier Center-Tapped Transformer ectifier DC = m DC = m DC = m DC = m 0.7 DC = m 2(0.7 ) DC = m 0.7 BFF1303 Electrical/Electronic Engineering 11 11

12 The ener is a diode operated in reverse bias at the ener oltage z. When The ener is on oltage across the ener is ener current: = The ener Power: P = When < The ener is off The ener acts as an open circuit BFF1303 Electrical/Electronic Engineering 12 12

13 To use of the ener diode as a regulator we must considered 3 cases i. i and fixed Step #1: Determine the state of ener diode by removing it from the network and calculating the voltage across the resulting open circuit. BFF1303 Electrical/Electronic Engineering 13 13

14 i f the ener is on and appropriate model can be substituted. f < the ener is off open circuit is substituted. Step #2: Substitute the appropriate equivalent circuit and solve for the desired unknown BFF1303 Electrical/Electronic Engineering 14 14

15 P where i BFF1303 Electrical/Electronic Engineering 15 15

16 ii. Fixed i and variable Due to the offset voltage z, there is a specific range of resistor values and load current that will ensure that ener is in the on state. Too small a load resistance will result in a voltage across the load resistor less than, and the ener device will be in the off state i BFF1303 Electrical/Electronic Engineering 16 16

17 Solving for min i Any load resistance value greater than the will ensure that the ener diode is in the on state and the diode can be replaced by its z source equivalent. For minimum the ener current exceeds the maximum current rating, M. The maximum current for the circuit is given by: max min BFF1303 Electrical/Electronic Engineering 17 17

18 Once the diode is in on state, the voltage across remains fixed at i and ener current is minimum when is a maximum is maximum when is a minimum Since is constant min max max min BFF1303 Electrical/Electronic Engineering 18 18

19 iii. Fixed and variable i For a fixed value of, the voltage i must be sufficiently large to turn the ener diode on. The minimum turn on voltage i min BFF1303 Electrical/Electronic Engineering 19 19

20 The maximum value of i is limited by the maximum ener current max max i max max BFF1303 Electrical/Electronic Engineering 20 20

21 For the ener diode network of figure below, determine,,, and P. i 16 1k 10 P max 30mW 1.2k Solution Since i and is fixed, then i 1.2k 16 1k 1.2 k 8.73 BFF1303 Electrical/Electronic Engineering 21 21

22 Since < the ener is off state and open circuit is substituted i 16 1k 1.2k i A P P 0W BFF1303 Electrical/Electronic Engineering 22 22

23 For the network of figure below, determine the range and that will result in being maintained at 10. Then determine the maximum wattage rating of the diode i 50 1k 10 M 32mA BFF1303 Electrical/Electronic Engineering 23 23

24 Solution Since i is fixed for the circuit shown and is a variable To turn on the ener diode, we need a small load resistance, then min i min 250 min max min min i 40m 32m 8mA 40 max min max 1.25k 40mA P P max max max 320 mw BFF1303 Electrical/Electronic Engineering 24 24

25 Determine the range of values of i that will maintain the ener diode of figure shown in the on state i 220 M 20 60mA 1.2k Solution Since i is a variable, then i min i min A BFF1303 Electrical/Electronic Engineering 25 25

26 max max max ma i max max i max BFF1303 Electrical/Electronic Engineering 26 26

BFF1303: ELECTRICAL / ELECTRONICS ENGINEERING. Analog Electronics: Bipolar Junction Transistors

BFF1303: ELECTRICAL / ELECTRONICS ENGINEERING Analog Electronics: Bipolar Junction Transistors Ismail Mohd Khairuddin, Zulkifil Md Yusof Faculty of Manufacturing Engineering Universiti Malaysia Pahang