- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 1 (48.7 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 2 (59.92 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 3 (67.44 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 4 (92.44 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 5 (69.45 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 6 (51.05 KiB) Viewed 53 times
- The Diode Is A Device Formed From A Junction Of N Type And P Type Semiconductor Material The Lead Connected To The P Ty 7 (22.52 KiB) Viewed 53 times
BREAKDOWN VOLTAGE Procedure: LEAKAGE CURRENT AVALANCHE CURRENT CURRENT REVERSE VOLTAGE FORWARD CURRENT ip=0 VOLTAGE Figure 1-2. I-V characteristics of a real diode When analyzing circuits, the real diode is usually replaced with a simpler model. In the simplest form, the diode is modeled by a switch (Figure 1-3). The switch is closed when the diode is forward biased and open when the diode is reverse biased. - + VD - + VD (VD<0, ip = 0) (ip>0. vp = 0) Figure 1-3 Equivalent Circuit of Diode 1) Finding Diode specifications Look up the characteristics of the diodes in your kit by making a web search. The specifications for different kinds of diodes vary. Include data sheet for each diode in your final lab report.
2) Obtaining I-V Characteristics: The current vs. voltage characteristics of the PN junction diode can be measured using the Discovery Board and the following connections. The green boxes indicate where to connect the Discovery board. a) Set up the breadboard with waveform generator output, W1, attached to one end of the resistor. The 2+ scope input is also connected here. The other end of the resistor is connected to one end of the diode as shown in the first diagram. The 2- scope input as well as the 1+ scope input is also connected to the second end of the resistor. The other end of the diode is connected to ground along with the 1- scope input. W1 GND 2+ R₁ 2- 1+ -01- Figure 1.4: Connection diagram for diode I vs. V curves Figure 1.5 shows the breadboard picture of the experimental setup shown in Figure 1.4 Figure 1.5: Breadboard picture of the diode I-V curve setup Include the picture of your breadboard with your lab report (you need to this for every lab even though it is not mentioned).
b) Set the waveform generator for a 100 Hz triangle wave with 3 volt amplitude and 0 volt offset. Figure 1.6 shows the waveform generator configuration. DWT 1-Arbitrary Waveform Generator I E Contd View Settings Select Channels Mode Shop A Channel 1 G 11 Enabled Bac Tig None SAWG¹ Advanced Custom Player Standard AWK A AWG 1: Burning Wat none Frequency 100 Ha M TOME 100Hz Run confrus Repeat Anclude PO SV Option Heb Preven Components Auto Vols V Running STEELLA BOR GERME OVE 10 Figure 1.6: Waveform generator setup Include the screen capture of your waveform generator window in your lab report (you need to this for every lab even it is not mentioned). PRE SV 4V 3V 2V TV OV -1V -2V -3V 4V SV c) The differential input of scope channel 2 (2+,2-) is used to measure the current in the resistor (and diode). In other words, with oscilloscopes we can only measure voltages. By measuring resistor voltage, we are actually measuring diode current (after scaling by a certain factor). d) The Single ended input of scope channel 1 (1+) is used to measure the voltage across the diode (1-input can be grounded). The Scope should be setup with channel 1 at 500mV per division and channel 2 set also at 500mV per division. The current flowing through the diode, Ip, is the voltage measured by channel 2 divided by the resistor value (1K in this example) e) Use the XY display mode to plot the voltage across the diode (scope channel 1) on the X axis vs. the current in the diode (scope channel 2) on the Y axis. See Figure 1.7 Figure 1.7 is still NOT the diode's I-V curve, as the left axis is simply the voltage on the resistor.
OWY 1-Ocoope L N DWRZUCKED Singh 25V 2V 1.5V 1V 65V DV asv -AV -15V 24 -25V Pn XY AAV Alt CAV Change Chart Type MA Temples C OT C 1616 Duned Sufee Doughnut 8SV Figure 1.7: Resistor voltage vs. Diode Voltage using XY display mode Area f) Include the screen capture of your scope screen in your lab report (Note that this is not yet the diode's IV curve). If we divide the numbers on left by R, it would be the diode IV curve however. We will do this in Excel. Chevel! g) Load the captured data into spreadsheet program like Excel. In order to do this, use the Export button on top left (See Figure 1.7) and export your data in .csv form (the very first option). Then, in Excel open a new spreadsheet. Go to Data-From Text and select the .csv file you just downloaded. Then you need to convert it into two columns in excel. Then, calculate the diode current Ip (which is Va value divided by 1000). Finally plot diode current ID vs Vp. Select two columns Ip and Vp and then go to insert Chart- choose XY. See Figure 1.8. Digh Q XY() De Evere Figure 1.8 Range 500 12 Offer Range 100 4 12
Remember to get the current vs. the voltage across the diode plot (plot 1). The diode voltage, current relationship is logarithmic. If plotted on log scale the line should be straight as seen in the second plot (plot 2). Include your version of plot I and plot2 in your report. 120€-03 1.000-03 8:00-04 6.00€-04 400E-04 2006-04 0:00-00 1006-09 1.006-04 1.006-06 1.006-06 0 0.3 01 02 035 04 I diode 03 045 04 Plot 1 Current vs. Voltage, linear scales 05 05 Idiode I 06 055 07 05 GM 07 Plot 2 Current vs. Voltage on log scale 1idade
Questions for Lab Report: 1. What is the mathematical expression for the diode current, ID, given the voltage across the diode VD? 2. Describe Piecewise Linear Model for a diode. For plot 1 shown above, what would be the value of V,