Full Wave Rectifier Project
Full Wave Rectifier Project
Rectifier uses the feature of Diode to allow the flow of current in only one direction. The device used for rectification is called rectifier.
Rectifiers are mainly two types, half wave rectifier and full wave rectifier.
Rectification is the process of converting an alternating voltage or alternating current into direct voltage or direct current”. The diode is applied as rectifier.
Types of Rectifier
1.) Half Wave Rectifier: This is the simplest form of the rectifier. It uses a single diode. Half wave rectifier is a circuit which rectifies only one of the halves of the ac cycle. During the half periods when P is positive, and N is negative, the diode is forward biased and will conduct. When P is negative, and N is positive, the diode is reverse biased and will not perform. The efficiency of the half-wave rectifier will be about 40.6%.
It is cheap, simple and easy to construct.
Half wave rectifier is widely used in the mobile charger or at the secondary coil of SMPS.
2.) Full Wave Rectifier: Output efficiency of full-wave rectifier is double of that of a half-wave rectifier. Ripple voltage is low and of higher frequency. Full wave rectifier is a circuit which rectifies both half cycles of the a.c. When P of the 1st diode is positive, the 1st diode is forward biased and will conduct. Now the 2nd diode will not lead as it is reverse biased. In all the half cycles either of the two diodes will be performing. The efficiency of a full wave rectifier is about 81.2 %, twice the ability of a half wave rectifier.
Full wave rectifier circuit rectifies the AC in both directions providing a DC signal for each AC cycle by using two or four Diodes.
For two diode rectifier circuit, it is necessary to have center tap transformer.
Four Diode rectifier also called Bridge Rectifier is practiced.
Difference between Half wave and Full wave rectifier
The main difference is that in full wave rectifier we use two diodes. For this when we apply a.c. Current to the rectifier then the first half wave get forward biased due to the direct diode and when the second half surge comes. Then at that time the second diode comes in action and gets forward biased. Thus output obtained during both the half cycles of the a.c. input .
Full wave rectifier
A full wave rectifier is a pattern 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 adjusted in a full wave rectifier which is an advantage over a half wave rectifier.
Like the half wave circuit, working of Full Wave Rectifier circuit is an output voltage or current which is purely DC or has some specified DC voltage.
Full Wave Rectifier Circuit
The full wave rectifier circuit consists of two power diodes connected to a single load resistance (RL) with each diode taking it, in turn, to supply current to the load resistor. When point A of the transformer is positive concerning point A, diode D1 conducts in the forward direction as indicated by the arrows.When point B is confident in the negative half of the cycle concerning C point, the diode D2 conducts in the forward direction, and the current flowing through resistor R is in the same path for both half-cycles of the wave.
The output voltage across the resistor R is the phasor sum of the two waveform; it known as a bi-phase circuit.The spaces between each half-wave developed by each diode is now being filled in by the other. The average DC output voltage across the load resistor is now double that of the single half-wave rectifier circuit and is about 0.637Vmax of the peak voltage by assuming no losses. VMAX is the maximum peak value in one half of the secondary winding and VRMS is the RMS value.
Working of Full Wave Rectifier
The peak voltage of the output waveform is the same as before for the half-wave rectifier provided each half of the transformer windings have the equal RMS voltage. To concern a different DC voltage output, different transformer ratios can practice. The disadvantage of this type of full wave rectifier circuit is that a more massive transformer for given power output needed with two separate but identical secondary windings makes this full-wave rectifying circuit costly compared to the Full Wave Bridge Rectifier circuit.
1st when the A.C. is provided 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 an electric current. During the next half cycle, the diodeD2 is forward, and D1 has converted. Hence D2 performs flow in the direction S2D2 ABEOS2and D1 does not show any current. In subsequent half cycles of the A.C present, the above processes has 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. Here 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. The capacitor also nearly filters all A.C components from the supply and resistance is connected to the required output. As this is a simple circuit, only one capacitor and strength are being used. But there will be a 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.
Advantages of Full Wave Rectifier
Full wave rectifiers have some fundamental advantages over their half wave rectifier counterparts.
The average (DC) output voltage is higher than for half wave rectifier, the output of the full wave rectifier has much less ripple than that of the half wave rectifier producing a smoother output waveform.
The advantages of a full-wave bridge rectifier are that it has a smaller AC ripple value for a given load and a lower reservoir or smoothing capacitor than an equivalent half-wave rectifier circuit.
It is the primary component to get D.C voltage for the elements which operate with D.C voltage. One can describe its working as a full wave rectifier project.
It is the heart of the circuit. Full wave rectifier uses the diode bridge. Capacitors are used to get rid of ripples. Based on the requirement of D.C voltage
Disadvantages of Half Wave Rectifier
Half wave rectification involves a lot of wastage of energy, and hence it is not preferred.
A small current flows in reverse bias due to minority charge carriers. As the output across (RL) is negligible.
The resulting d.c. Voltage is not steady enough for some purpose. The following device is practiced when a very constant d.c. energy is required
For bridge type, no center tap required on the transformers. Here much smaller transformers are used. The bridge rectifier operated for high voltage application. For the same secondary voltage, the output voltage is twice that of the center tapped full wave rectifier.The bridge rectifier with filter section is buildup. A.c and D.C voltages can measure for efficiency is assumed.
By doing this project, we came to knew that a full wave bridge rectifier could be built without center tapping transformer. And also we arrived to find the efficiency of whole wave rectifier.
At the same time, some disadvantages are there. Here two other diodes are required, and voltage regulation is not satisfactory.