1. Lab Experiment: 2 Objectives: To understand the diode’s characteristics. Construct the Full wave bridge rectifier. Explain it’s wave form. Name of the Experiment: Full Wave Rectifier Characteristics.

2. Circuit Analysis Full-wave Rectifiers allow both half cycles of AC to pass. Figure 4a is the circuit of a Full-wave Bridge Rectifier, it is constructed by four Diodes, during each half cycle only 2 out of 4 Diodes are conducting, Figure 4b and Figure 4c. During positive half cycles, as shown in Figure 4b, current is conducted through D4, the load Resistor and D6. Meanwhile, D3 and D5 are reverse-biased, thus no current flows through them. During negative half cycles, as shown in Figure 4c, current flows through D3, the load Resistor and D5. Meanwhile, D4 and D6 are reverse-biased.

3. Figure 4a: Full-wave Rectifier circuit Figure 4b: Equivalent rectifier circuit during the positive half cycles

4. Circuit Analysis ( Cont. ) During both half cycles, current flows through the load resistor in the same direction (from up to down). The voltage across the load resistor is always positive. The input and output voltage Waveforms of a Full-wave Rectifier are shown in Figure 5a and Figure 5b respectively. The Full-wave Rectifier utilizes both half cycles of the input, which makes it the most popular rectifier configuration.

5. Figure Experimental Figure 5a: Input AC Voltage WaveformFigure 5b: Output DC Voltage Waveform after Full-wave Rectification

6. If a Capacitor is added in parallel with the load resistor of a Rectifier to form a simple Filter Circuit, the output of the Rectifier will be transformed into a more stable DC Voltage, Figure 6. At first, the capacitor is charged to the peak value of the rectified Waveform. Beyond the peak, the capacitor is discharged through the load resistor until the time at which the rectified voltage exceeds the capacitor voltage. Then the capacitor is charged again and the process repeats itself.

7. Figure ( Experimented ) Figure 6: Output Voltage Waveform (solid line) of Full-wave Rectifier with Filter Capacitor added