Lab 4 - Rectifier Circuits

.pdf

School

South Texas College *

*We aren’t endorsed by this school

Course

ARCE-235

Subject

Electrical Engineering

Date

Feb 20, 2024

Type

pdf

Pages

Uploaded by DoctorTigerPerson61

ELEE 3101 Electronics I Lab Lab 4: Rectifier Circuits Page 1 of 7 Lab 4: Rectifier Circuits Student name: ________________________________ Student ID: ____________ I. Introduction Once that you have been introduced to diodes, it is time to learn about its applications. A diode rectifier forms an essential building block of the dc power supplies required to power electronic equipment. On this lab, you will use diodes to build different rectifier circuits, compare their operation modes and determine the best to be implemented. II. Objectives • Identify the different rectification circuits. • Analyze the different waveforms at the output of each rectifier circuit. • Describe the operation of each rectifier circuit. III. Equipment Required • Digital Multimeter • Dual-Trace Oscilloscope • Function Generator • Breadboard • Miscellaneous cables IV. Material Required • 4 Conventional Diode 1N4007 (Rectifier diode) • Resistors of different values • Jumper wires

ELEE 3101 Electronics I Lab Lab 4: Rectifier Circuits Page 2 of 7 V. Before the Lab As you may know, all electronic devices and equipment operate with a dc voltage ( “ electronic ” not “ electric ” , remember that is not the same), some of them uses batteries to work, but there are some others that requires to be connected to a power outlet in the wall, so that they can work, or that they can recharge their internal battery, however, you may remember the voltage that we obtain from the outlets at home, school, or work, is a ac voltage, so it is necessary to perform a conversion from ac to dc, and there is where a diode rectifier is implemented (Figure 1). The first block in a dc power supply is the power transformer, it reduces the amount of voltage on the input to the value required to yield the particular dc voltage output of the supply, it also provides electrical isolation from the electronic equipment and the power- line circuit. The diode rectifier converts the input sinusoid 𝑣 𝑆 to a unipolar output, which will have a pulsating waveform. Although this waveform has a nonzero average or a dc component, its pulsating nature makes it unsuitable as a dc source for electronic circuits, hence the need for a filter. The variations in the magnitude of the rectifier output are considerably reduced by the filter block. Depending on the application, three different rectifier circuits can be constructed. Figure 1.- Block diagram of a dc power supply. 5.1 The Half-Wave Rectifier The half-wave rectifier utilizes alternate half-cycles of the input sinusoid. Figure 2(a) shows the circuit of a half-wave rectifier. Using the more realistic constant-voltage-drop diode model, we obtain 𝑣 𝑜 = 0, 𝑣 𝑆 < 𝑉 𝐷 𝑣 𝑜 = 𝑣 𝑠 − 𝑉 𝐷 , 𝑣 𝑆 ≥ 𝑉 𝐷

ELEE 3101 Electronics I Lab Lab 4: Rectifier Circuits Page 3 of 7 The transfer characteristic represented by these equations is sketched in Fig. 2(b), where 𝑉 𝐷 = 0.7 V or 0.8 V . Figure 2(c) shows the output voltage obtained when the input 𝑣 𝑆 is a sinusoid. Figure 2.- a) Half-Wave rectifier schematic. b) Transfer characteristic of the rectifier circuit. c) Input and output waveforms. 5.2 The Full-Wave Rectifier The full-wave rectifier utilizes both halves of the input sinusoid. To provide a unipolar output, it inverts the negative halves of the sine wave. One possible implementation is shown in Fig. 3(a). Here the transformer secondary winding is center-tapped to provide two equal voltages 𝑣 𝑆 across the two halves of the secondary winding with the polarities indicated. Note that when the input line voltage (feeding the primary) is positive, both of the signals labeled 𝑣 𝑆 will be positive. In this case 𝐷 1 will conduct and 𝐷 2 will be reverse biased. The current through 𝐷 1 will flow through 𝑅 and back to the center tap of the secondary. Now, during the negative half-cycle of the ac line voltage, both of the voltages labeled 𝑣 𝑆 will be negative. Thus 𝐷 1 will be cut off while 𝐷 2 will conduct. The current conducted by 𝐷 2 will flow through 𝑅 and back to the center tap. The important point, however, is that the current through 𝑅 always flows in the same direction, and thus 𝑣 𝑂 will be unipolar, as indicated in Fig. 3(c).

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version