Full-wave rectifier circuit, working principle of full-wave rectifier circuit

Full wave rectifier circuit

If some adjustments are made to the structure of the rectifier circuit, a full-wave rectifier circuit that can fully utilize electric energy can be obtained. Figure 5-3 is the electrical schematic diagram of the full-wave rectifier circuit.

The working principle of full-wave rectifier circuit:

A full-wave rectifier circuit can be regarded as a combination of two half-wave rectifier circuits. A tap needs to be drawn in the middle of the secondary coil of the transformer to divide the secondary coil into two symmetrical windings, thereby drawing out two voltages e2a and e2b of equal size but opposite polarity, forming e2a, D1, Rfz and e2b, D2, Rfz. Two energized circuits.

The working principle of the full-wave rectifier circuit can be explained by the waveform diagram shown in Figure 5-4. Between 0 and π, e2a is a forward voltage to Dl, D1 is turned on, and a positive and downward voltage is obtained on Rfz; e2b is a reverse voltage to D2, and D2 is not turned on (see Figure 5-4(b) ). In the π-2π time, e2b is a forward voltage to D2, D2 is turned on, and the voltage obtained on Rfz is still a positive and downward voltage; e2a is a reverse voltage to D1, and D1 is not turned on (see figure 5-4(C).

Repeatedly, since the two rectifier elements D1 and D2 conduct electricity in turn, the current in the same direction passes through the load resistor Rfz during the positive and negative half cycles, as shown in Figure 5-4(b). Therefore, it is called full-wave rectification. Full-wave rectification not only utilizes the positive half cycle, but also cleverly utilizes the negative half cycle, thereby greatly improving the rectification efficiency (Usc =0.9e2, twice as large as half-wave rectification).

The full-wave filter circuit shown in Figure 5-3 requires the transformer to have a secondary center tap that makes both ends symmetrical, which brings a lot of trouble to the production. In addition, in this circuit, the maximum reverse voltage that each rectifier diode withstands is twice the maximum secondary voltage of the transformer, so diodes that can withstand higher voltages need to be used.

Figure 5-5(a) is a bridge rectifier circuit diagram , and (b) is a simplified drawing.