Full wave Rectifier investigatory Project PDF
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INTRODUCTION
A full wave rectifier is a device which is used to rectify all the alternating current components in an alternating supply and make it purely a direct current. The two alternating halves of an alternation current are rectified in a full wave rectifier which is an advantage over a half wave rectifier. Most electronic devices cannot withstand very high voltage or alternating current due to its intense high power. The use of batteries in all devices is not practical as their replacement and durability is a huge problem as the device has to be dismantled each time for such a replacement. So, these rectifiers are used in most of the electronic devices like TV’s, Radios, Chargers, and Lightings etc.
MATERIAL REQUIRED
- Connecting wires
- A plug
- Single lead wire – 2m
- 3 nuts & Bolts 2 to 3cm length
- Circuit board
- A Transformer
- A capacitor
- A Resistor (1 K Ω)
- P-N junction diodes
- A LED
- Insulation tape, Blades, soldering wax, soldering lead, soldering iron &sand pape
CIRCUIT DIAGRAM
Connection details:
Connections are done as in the circuit. The A.C. supply is given to both the input wires of the transformer and the two ends of the secondary coil is given to the P side of the two diodes and the N side of the diodes are twined and then connected to one end of the capacitor and the other end to the centre tap lead and to the resistor. Further, the other end of capacitor with the diode connect ion is connected to the other end of the resistor. Connect 2 leads on both the ends of the resistor to measure the output and this is connected to the +ve & -ve terminals of the bulb.
WORKING
1st when the A.C. is supplied to the transformer, it steps down the 230V main supply to 6 volts. It has a capability of delivering a current of 500mA. The 6 volts A.C. appearing across the secondary is the RMS value and the peak value is 8.4 volts. During the 1st half cycle of the A.C. input Diode D1 is forward biased and a current ‘I’ flows in the circuit in the direction S 1D1 ABEOS1. During this time diode D2 is reverse biased. So, it does not conduct any electric current. During the next half cycle, the diodeD2 is forward and D1 is reversed. Hence D2 conducts current in the direction S2D2 ABEOS2and D1 does not conduct any current. In subsequent half cycles of the A.C current the above processes are repeated.
In both the half cycles it is clear that current flows through the resistor in only one direction ABE. Even though the voltage across RL is unidirectional it will still contain a few A.C components. This is filtered and made smooth using a capacitor, which filters 99% of the A.C current. A resistor is then used to adjust the output voltage. Capacitor also nearly filters all A.C components from the supply and resistance is adjusted for the required output. As this is a simple circuit, only one capacitor and a resistance are being used. But there will be slight factor of A.C. current still left in the output but it is negligible. The output Direct Current and voltage light up the LED.
GRAPHS
APPLICATION
- Because of their low cost compared to centre tapped, they are widely used in power supply circuit.
- This can be used to detect the amplitude of modulated radio signal.
- Bridge rectifiers can be used to supply polarized voltage in welding.
- In daily life, rectifier find use in mobile chargers.
- These rectifiers are used in most of the electronic devices like TV’s, Radios, Chargers, and Lightings etc.
MERITS AND DEMARITS
Merits:
- The rectification efficiency of full wave rectifier is double of that of a half wave rectifier.
- The ripple voltage is low and of higher Frequency in case of a full wave rectifier so simple filtering circuit is required.
- Higher output voltage higher output power and higher TUF in case of a full wave rectifier
- In a full wave rectifier, there is no problem due to DC saturation of the core because the DC currents in the two halves of the transformer secondary flow in opposite directions
Demerits:
- Full wave rectifier needs more circuit elements and is costlier.
COMPARISION BETWEEN FULL WAVE AND HALF WAVE RECTIFIER
BIBLIOGRAPHY / REFERENCE
- wikipedia.com
- Google search engine
- Knowledgecycle.in
- Physics NCERT book for class XII