Question: learning objectives by the end of this experiment you should...
By the end of this experiment, you should be able to:
· Measure and plot the forward and reverse-biased IV characteristics for a diode.
· Measure and plot the IV characteristics for Zener diodes.
· Measure the ac resistance of a diode.
Resistors: 1 ´ 330W, 1 ´ 1.0MW, 560W 5W Components: 1 ´ 1N4148or equivalent, 1 ´ 1N4740 5.0V
· Tektronix PS280 DC Power Supply
· Fluke 45 Dual Display Multimeter
Answer the following questions:
i. Silicon Diode Characteristics
a. What material is commonly used to manufacture diodes?
b. The semiconductor diode is basically a pn junction. Draw a simple diagram to show thecross section of the diode. On the diagram, indicate the p and n regions as well as the anodeand the cathode of the diode.
c. Sketch the I-V characteristic of an ideal diode.
ii. Zener Diode
a. Sketch the general Zener diode characteristics indicating all importantpoints.
b. State two differences between normal diodes and Zener diodes.
A normal diode will be permanently damaged for a large reverse current, but a zener diode will not. Diodes are normally used for rectification, whereas zener diodes are used for voltage regulation.
IN-LAB ACTIVITIES (Silicon Diode- Characteristic)
1. Measure and record the resistance of the resistors. Then check your diode with the multi-meter.Measure the forward and reverse resistances of the diode. Record and tabulate the data.
2. Construct the forward-biased circuit shown in Figure 1-1. Set the power supply for zero volts.
3. Monitor the forward voltage drop, VD,FOR, across the diode, D1. Slowly increase VS to establish0.35V across the diode. Measure the voltage across the resistor, VR1, and compute ID FOR.Record and tabulate the data in Table 1-1.
4. Repeat step 3 for voltage VD,FOR of 0.40V, 0.45V, 0.50V, 0.55V, 0.60V, 0.65V, 0.70V, and 0.75V.
5. Connect the reverse-biased circuit shown in Figure 1-2. Set the power supply, VS to 5.0V, and thento 10.0V, 15.0V, 20.0V, and 25V. Measure VD REV and compute ID,REV for each voltage applied. Record and tabulate the data in Table 1-2.
6. By using all the data taken plot a forward and reverse-biased diode curves graph (ID versus VD).
LAB 1 REPORT
i. Silicon Diode Characteristic
a. Describe your observation/understanding based on the plotted forward biased diode curve graph.
b. Discuss the difference from the experimental I-V plot, compared to the ideal I-Vcharacteristic drawn in the pre-lab question.