1. Kankeshwaridevi institute of technology
Subject Code :
Name Of Subject : ELECTRONICS DEVICES AND CIRCUITS
Topic : RECTIFIERS
Name of Faculty : MRUNALI PATEL
Name of Students: MOKHA DIVYA
EN.NUMBER:

2. Explanation of rectifier
Rectifier is an electronic device which is used for converting an alternating voltage or current in to a unidirectional voltage or current.

3. Operation :
The basic building block of a regulated dc power supply are:
A step down transformer
A Rectifier
Filter
A voltage regulator
Step down transformer is used to reduced the ac mains voltage to an adequately small value .
The type of rectifier used are half wave rectifier , full wave rectifier and bridge rectifier.
This voltage is converted into a pulsating dc voltage by the rectifier.
The pulsating dc voltage at the rectifier output is converted into a ripple free steady dc voltage by the filter circuit .
The filter output voltage is very close to the pure dc voltage .

4. Rectifier circuits:
Rectifier is a circuit which converts an alternating (ac)voltage into (dc) voltage.
The classification of rectifier is as shown in fig.1
Rectifier circuit
Half wave rectifier full wave rectifier
FWR with center tapped transformer half wave rectifier

5. Half wave rectifier
In half wave rectifier , the rectifier is only during one half cycle of the ac supply.
So output is produced only in that half cycle.
The output is suppressed in the other half cycle.
The conduction takes place only in one half cycle of supply , hence the name of this circuit is half wave rectifier.
T1 is the input step down transformer.
RL is the load resistance . The resistance of diode in the on stat be Rf and let the resistance of the secondary winding be Rs.

6. Analysis of half wave rectifier
Average load current
RMS load current
Ripple factor
Rectification efficiency and TUF
Average load voltage
RMS load voltage
Voltage regulation

7. Full wave rectifier with center tapped transformer
The full wave rectifier it consists of a step down center tapped transformer T1, two diode and purely resistive load RL.
In the half wave the load current flows in only one half cycle of the supply but in the full wave rectifier it flows in both the half cycle of ac supply.

8. Advantages of full wave rectifier
Low ripple factor as compared to HWR
Better rectification efficiency
Better TUF
Higher values of average load voltage and load current
No possibility of transformer core saturation.
Disadvantages of full wave rectifier
Sine PIV of the diode is 2 Vm , size of the diode is larger and they are more costly.
Cost of the center tapped transformer is high

9. Applications of FWR: 1. Laboratory power supply 2
Applications of FWR: 1. Laboratory power supply 2. high current power supplies. 3. battery chargers. 4. power supplies for various electronic circuit.

10. Ckt explanations

11. COMPONENT REQUIRED 1. MICRO CONTROLLER (AT89C51) 2
COMPONENT REQUIRED 1.MICRO CONTROLLER (AT89C51) 2.CRYSTAL OSCILATOR (12 MHZ) 3.LIGHT EMITTING DIODE (RED,ORANGE,GREEN 4 NO’S) 4.RESISTOR (1 K OHM 4 NO’S) (460 K OHM 4 NO’S) (100 K OHM 4 NO’S) (120 OHM 1O NO’S) 5.CAPACITOR :-33pF 6.MISCELLALEOUS COMPONENT REGULATED POWER SUPPLY OF 5V CIRCUIT CONNECTING BOARD CONNECTING WIRES

13. Microcontroller - Microcontroller unit is constructed with ATMEL 89c51 microcontroller chip. The ATMEl AT89c51 is a low power, higher performance CMOS 8 bit microcomputer with 4K bytes of flash programmable and erasable read only memory (PEROM). - The 8051 series of microcontrollers are highly integrated single chip microcomputers with an 8 bit CPU memory, interrupt controller, timers, serial i/o and digital i/o on a single piece of silicon. - The 8051 is an 8- bit machine.

14. Crystal oscilator
- A crystal oscillator uses the mechanical resonance of a vibrating piezoelectric
material to generate a very stable clock signal.
- The frequency is usually used to
provide a stable clock signal or to keep track of time; hence, crystal oscillators are
widely used in RF and digital circuits.

15. LIGHT EMMITING DIODE
A light-emitting diode (LED) is a semiconductor light source. The color of the light is determined by the energy gap of the semiconductor.
PRINCIPLE:
When a light-emitting diode is forward biased electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence. Electroluminescence (EL) is an optical and electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field. The wavelength of the light emitted, and thus its color depends on the band gap energy of the materials forming the p-n junction. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.

16. Future Planning

17. Advantages - Adv. Of TLC is cover many areas but the main area is safety. - Traffic lights in heavily congested areas. - A pedestrains to safely cross the road without having to risk. - In traaffic lights can save a city money.

18. Disadvantages - Lights were designed to organize a residental streets.

19. Application - Bridge construction - 2 lane rode control - Bridge painting - Event traffic control - Natural disaster traffic control - Emergency response