Ikki yarim davrli to‘g‘rilagichni foydali ish koeffisiyenti (ɳ) ning matematik ifodasini aniqlash Annotatsiya

Theoretical part. Modern electronics is based on electronic devices made of semiconductor materials and is rapidly evolving. From the smallest details of devices to integrated circuits, microcontrollers and even microprocessors, semiconductor materials are being created. Therefore, a quality AC power supply is required to ensure proper and smooth operation of these devices. Because the electricity in our networks is sinusoidal, we need two half-cycle rectifiers. Our article explains that we can rectify alternating current using semiconductor rectifiers. Semiconductors are widely used in electronics, and almost all modern electrical appliances - from computers to cell phones - are based on semiconductor technology.


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FIGURE 1. Full-wave rectifier with center-tapped transformer.

ain part: There are two types of single-phase full-wave rectifier, namely, full-wave rectifiers with center-tapped transformer and bridge rectifiers. A full-wave rectifier with a center-tapped transformer is shown in Fig.1. It is clear that each diode, together with the associated half of the transformer, acts as a half-wave rectifier. The outputs of the two half-wave rectifiers are combined to produce full-wave rectification in the load. As far as the transformer is concerned, the dc currents of the two halfwave rectifiers are equal and opposite, such that there is no dc current for creating a transformer core saturation problem.

The voltage and current waveforms of the full-wave rectifier are shown in Fig. 10.4. By observing diode voltage waveforms vD1 and vD2 in Fig. 10.4, it is clear that the PIV of the diodes is equal to 2Vm during their blocking state. Hence the VRRM rating of the diodes must be chosen to be higher than 2Vm to avoid reverse breakdown. (Note that, compared with the half-wave rectifier shown in Fig. 10.1, the full-wave rectifier has twice the dc output voltage, as shown in Section 10.2.4.) During its conducting state, each diode has a forward current which is equal to the load current, therefore the IFRM rating of these diodes must be chosen to be higher than the peak load current, Vm = R, in practice. Employing four diodes instead of two, a bridge rectifier as shown in Fig. 10.5 can provide full-wave rectification without using a center-tapped transformer. During the positive halfcycle of the transformer secondary voltage, the current flows to the load through diodes D1 and D2. During the negative halfcycle, D3 and D4 conduct. The voltage and current waveforms of the bridge rectifier are shown in Fig. 10.6 As with the fullwave rectifier with center-tapped transformer, the IFRM rating of the employed diodes must be chosen to be higher than the peak load current, Vm = R. However, the PIV of the diodes is reduced from 2Vm to Vm during their blocking state.