 Hello everyone. Welcome to this video lecture. Myself Deepali Vardkar, working as assistant professor at WIT Solapur. In this video lecture, we will study full wave rectifier. These are the learning outcomes. At the end of this video lecture, student will be able to examine working of center tap full wave rectifier and bridge rectifier. Also student will be able to draw the input and output waveforms of center tap full wave rectifier and bridge rectifier. The full wave rectifier is the type of rectifier which converts both half cycles of AC signal into pulsating DC signal. The full wave rectifier further divides into two types center tap full wave rectifier and bridge rectifier. So let us study center tap full wave rectifier. Here the AC source is connected to the primary of the transformer. This rectifier is called as a center tapped full wave rectifier because here the transformer which is used, that transformer is center tapped. Here the additional wire is connected exactly middle of the second winding. So it is called as a center tapped transformer. This wire is adjusted such that it falls exactly middle of this winding. So this wire is at zero volt or it is get connected to the ground. The center tapped transformer works like a normal transformer. That is it can convert input AC voltage, it can decrease the input AC voltage or it can increase the input AC voltage level. But it also has one additional feature that the secondary winding of this transformer divides the input AC signal into two parts. The upper part produces the voltage V A, the lower part produces voltage V B. So if we observe the voltage across the load that voltage will be the combination of these two voltages V A plus V B. So the upper part of the secondary winding is connected to diode D1 and lower part of the secondary winding is connected to diode D2. Both the diodes are get connected to the load resistor REL. So this is the construction of center tapped full wave rectifier. During the positive half cycle of input AC signal, let us see the working of full wave rectifier. The AC signal is given to the primary of the center tapped transformer. Then this center tapped transformer decrease the voltage level of this AC signal. Then during the positive half cycle of AC signal, the terminal 1 becomes positive, the terminal 2 becomes negative. So the positive voltage is get applied to the P side that is the anode of diode D1 and negative voltage is applied to the P side of that is the anode of diode D2. So due to this the diode D1 becomes forward bias and diode D2 becomes reverse bias. So diode D1 conducts whenever there is a positive half cycle of input AC signal and current flows through this load REL. So here during the positive half cycle of input AC signal, the current flows only in upper part of this circuit. So the voltage present across the load that is the positive half cycle or VA. Now during the negative half cycle of input AC signal, the first AC signal is applied to the primary of the transformer. This secondary of the transformer the decreased AC voltage level. This AC voltage level whenever applied to this 2 diode, during the negative half cycle of this input AC signal, the terminal 1 becomes negative and terminal 2 becomes positive. And due to this this negative voltage is get applied to the P side that is the anode of diode D1 and positive voltage is get applied to the anode of diode D2. So this diode D1 is becomes reverse bias and diode D2 is becomes forward bias. So during the negative half cycle of input AC signal, the current flows only in lower part of this circuit. So there is a zero current at the upper part of the circuit. So during the negative half cycle of input AC signal, the again the positive half cycle signal present across the load that is the VB. Now the diode D1 and diode D2 both diodes are get connected to the load resistor REL. So during the positive half cycle diode D1 conducts and during the negative half cycle diode D2 conducts. So the load which is flows through the load that is the load current, it is the combination of diode D1 and diode D2 current. So this is the input output waveform representation. This is the AC input signal. Then this is the representation of current waveform which is flows through the diode D1. This is the representation of current flows through the diode D2 and across the load the current which flows through the load that is the combination of D1 current and D2 current. So this is the output waveform from the load. Now the second type of full wave rectifier that is the bridge rectifier. The bridge rectifier here four diodes are used D1, D2, D3 and D4. These four diodes are connected in a bridge configuration or in a closed loop. Now here the AC source is connected to the terminal 1 and 2 and the load is connected across terminal 3 and 4. So this is the construction of bridge rectifier. The one advantage is of bridge rectifier. So that is here the center type transformer is not required. During the positive half cycle of input AC signal whenever the AC source is applied to the terminal 1 and 2 during the positive half cycle of input AC signal the terminal 1 becomes positive and terminal 2 becomes negative. So due to this the diode A and diode C both diodes becomes forward bias and diode D and diode B both diodes becomes reverse bias. So current flows through point 1 to 4, 4 to 3, 3 to 2. So current flows in this direction and also current flows through the load. During the negative half cycle of input AC signal the terminal 1 becomes negative and terminal 2 becomes positive. Due to this the diode D and diode B both this diode becomes forward bias and diode A and C becomes reverse bias. So the current flows in this positive half cycle this current flows through point 2 to 4, 4 to 3 and 3 to 1 and hence current also flows through the load resistance REL. So for both the positive as well as negative half cycle the direction of current flowing through the load is same and that is nothing but DC current. These are the input output waveforms this is the representation of input AC signal then the current flows through the diode A and C then during the negative half cycle of input AC signal this is the representation of current flows through the diode B and D as all these diodes A to D connected to the load so at the load the combination of the current which flows through diode A to D so this is the output waveform through the load. Now characteristic of full wave rectifier the center tap full wave rectifier uses 2 diodes the preach rectifier uses 4 diodes the maximum efficiency of center tap rectifier is 81.2% and maximum efficiency of bridge rectifier 81.2% then peak inverse voltage for center tap it is equal to 2Vm and for bridge it is Vm then DC voltage across the load that is 2Vm upon pi and for bridge also 2Vm upon pi so Vm here is the peak voltage then transformer utilization factor for center tap rectifier it is 0.693 and for bridge it is 0.812 and ripple factor for center tap rectifier it is 0.48 and for bridge it is also 0.48 now already in the previous lecture we have seen the half wave rectifier now what is the difference between half wave rectifier and full wave rectifier pause the video for a while and think so this is the difference between half wave rectifier and full wave rectifier the function of half wave rectifier it passes only one half cycle of applied input AC signal and blocks the other the function of full wave rectifier it passes both half cycles of applied input signal the number of diodes which are required for half wave rectifier only one and for full wave rectifier 2 to 4 the rectification efficiency of half wave rectifier is 40.6% and for full wave rectifier it is 81.2% ripple factor for half wave rectifier 1.21 and for full wave rectifier it is 0.482 so ripple factor indicates that performance of half wave rectifier is greater than half wave rectifier transformation utilization factor for half wave rectifier is 0.286 and for full wave rectifier is 0.692 voltage regulation for half wave rectifier is good and for full wave rectifier it is better these are the references thank you