Diode has become a very common part of electronics, now days it is the necessary component of an electronics circuits. When we come to know about the diode applications in our daily life or common applications in electronics technology, Rectifiers come in our mind very first. So the here I will tell the basic principles of the diode in the rectifiers. There are two common rectifiers one is half wave rectifier and second is the full wave rectifier. Let come to know about these two types of circuits.
Half Wave Rectifier:
In half wave rectifier the diode converts the input ac voltages to pulsating dc voltages. We know well that there are two portions of ac sine wave, one is positive and other is negative, when the negative cycle of the ac sine wave reaches to diode, it blocks current flow, so at this point the output voltages become zero volts. Diode introduces a 0.6V drop so output peak is 0.6V smaller than the input peak. The output frequency of the half wave rectifier is the same as the input frequency. The figure diagram of the circuit is shown in below.
Full wave Rectifier:
The next important application of the diode in electronics technology is in the full wave rectifier. At above you have seen the half wave rectifier, which only process the one half cycle, but the full wave as the name states , it process the both cycles of the an voltages. A full wave rectifier does not block the negative swing but half wave rectifier blocks. Full wave rectifier transforms them into positive swing at the output. To gain an understanding of device operation, follow current flow through pairs of diodes in the bridge circuit. It is easy seen that one pair of diodes (D3 – Rout – D2) allows current flow during the positive half cycle of incoming voltages the other pair of diodes (D4-Rout-D1) allows current flow during the negative half cycles of the input voltages. Output voltage peak of the full wave rectifier is 1.2 V below the input voltage peak. The output frequency is twice the input frequency in case of full wave rectifier as we can see this all the process in the below diagram,
I hope now your concept about the full wave bridge rectifier will be very clear. Now the next diode application is AC to DC Power Supply. This is very important application of diode, because in this process we can get the pure DC voltages for our circuits.
AC to DC Power Supply:
In the diode applications, an important feature comes. To obtain power supply from AC (Alternating Current) to DC (Direct Current), we use a transformer with full wave bridge rectifier. Here the transformer is used to step down the input voltages and next part is full wave bridge rectifier, which converts these AC input voltages to pulsating DC voltages. Pulsating DC voltages are not pure DC voltages, to make the small pulses smooth, we use a filter capacitor to make smooth the output voltages. Here one important thing is that the capacitor being used for filtering process must be large enough to store sufficient charge so as to provide a steady current supply to the load. RLoad C >>1/ f here f is rectified signal’s frequency (120 Hz). Whole the stated process you can see in the below figure, I hope your concept regarding this type of AC to DC Power Supply will be clear now.