Lab Report

Group Number : 02Group Members :

Instructor Name SignatureRony Kumer Saha __________

Report approval status: Approved Partially approved Not approved

Name

1. Md. Solayman Khan2. Faisal Ahmed3. Shamima Akter

ID

2013-1-80-0222013-1-80-0162012-3-80-014

Course Name : Electronic Circuit-ICourse Code : EEE102Experiment No :01Experiment Name :

Signature

____________________________________

Date of Experiment : --/--/2014Date of Submission : --/--/2014

Problem Statement: In this experiment, we are supposed to find out the basic characteristics of a p-n junction diode .We will also find out the I-V characteristics and also will model the forward conduction of a Diode. Objective Of The Experiment: The main objective of this experiment was to measure the I-V characteristics and also to find the large and small signal models of forward conduction of p-n junction diode. Significance Of The Experiment: The main significance of this experiment is that , this experiment allows us to know the characteristics of p-n junction diode.

Required Component And Instrument: 1. Diode (1pc) 2. Resistor (1K-ohm) [ Measured 0.983 K-ohm] 3. Digital multimeter Experimental Set Up: At first we have to set the diode and resister into the breadboard and make a series circuit. Then we have to connect the wears with sources. After that, we have to find the expected values and make a graph for I-V characteristics. At last, we have to define the errors during experiment and make a conclusion on how to overcome.

Experimental Data Table: VD (volt) VR (volt) ID (mA) = VR/R (K-

Ohm) 0 0 0 0.43 0.04 0.0407 0.53 0.46 0.4679 0.57 0.91 0.9257 0.59 1.39 1.414 0.60 1.91 1.943 0.61 2.41 2.451 0.62 2.92 2.970 0.63 3.36 3.4181 0.64 3.85 3.9163 0.64 4.34 4.415 0.65 4.84 4.9237 0.65 5.34 5.4323 0.66 5.83 5.9308 0.66 6.32 6.4292 0.67 6.81 6.9277 0.67 7.32 7.4465 0.67 7.80 7.9348 0.68 8.33 8.4740 0.68 8.79 8.9420 0.68 9.32 9.4811 0.68 9.82 9.9898 0.69 10.30 10.4781 0.69 10.83 11.0103 0.69 11.32 11.515

Required Calculation: From the data table we know, If VD = 0.6 volt then VR = 1.91 volt and R=0.983 K-ohm (by measured) To find ID we use, ID = VR/R Or, ID = 1.91

0.983

= 1.943 A We always get the value of ID by using this equation. There are another equations which required to solve the lab but that part will include in appendices and lab report question.

Result: In the experiment, We find ID =1.91 mA For VR = 1.91volt Result Analysis: If we consider theoretically than R = 1 K-ohm (given in lab manual ) Then if VR = 1.91volt We find ID = 1.91

1= 1.91 mA

The difference between measured and theoretical value is = (1.943 – 1.91) mA = 0.033 mA Recommendation: 1. The error is not significant because due to equipment error such as in lab manual there given that R is 1 K-ohm but by measuring we find that R is 0.983 k-ohm. For that there is no trouble during the time of lab. It is too little difference, so there no effect on resistor and it gives proper value.

Report Question And Answer

Answer to the question no 1

Graph-1: Graph of the I-V characteristics using experimental Data

-2

0

2

4

6

8

10

12

14

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

I(mA)

Y-Values

Answer to the question no 2 When ID1 = 2mA then VD1 = 0.6040 V And ID2 = 2.5mA then VD2 = 0.6145 V Now to find n we can use this equation , VD2-VD1=nVT ln(ID2/ID1)

=>n =VD2-VD1/VT ln(ID2/ID1)

=>n= (0.6145−0.6040)0.0259 ln (2.5

2 )

=>n =1.82

ID = ISe[VD\nVT]

=>IS= ID/ e^[VD/nVT]

=>IS = 2/ e^[0.604/1.82×0.0259]

= 0.0058 mA

Answer to the question no 3

Here the cut in or built in voltage is VDO = 0.56 V

Answer to the question no 4 When ID = 2mA, VD = 0.6040 V Now, VD = VDO + IDrD

rD = (VD-VD0)/ID

= (0.6040 – 0.56)/2 = 0.022 K

Answer to the question no 5

Small signal resistance, rd=nVT/ ID =(1.82×0.0259)/2 =0.0234K Value of rd Value of rD 0.0234K 0.022K Comment: The values of rD andrd are same. There is a little bit difference between (0.0234 -0.022) K = 0.001 which must be avoidable.

Answer to the question no :6

Figure1:Figure for the experimental circuit

Figure2:Simulated result of circuit 1

Conclusion: From this lab , we have learned about the characteristics of diodes. From this experiment we’ve learn that Diodes will prevent currents in reverse directions. From the I vs. V characteristics we know about forward, reverse and no bias concept. Our concept is increasedabout diode and I vs. V characteristics by doing this experiment . Reference: 1. Electrical devices and circuit theory by Robert L. boylestad and L.nashelsky. 2. Microelectronic Circuits by Sedra Smith . 3. http://en.wikipedia.org/diodes

Appendix: 1. To do the experiment easily ohms law helps us. By using ohms law we can easily find voltage and current.

2. We can easily find the I vs. V characteristics by using Shockley ideal equation.

The equation state that,

Where,

I is the diode current IS is the reverse bias saturation current (or scale current) VD is the voltage across the diode VT is the thermal voltage, and n is the ideality factor.

3. We can also use piecewise linear model to understand the lab easily. The equation is VD = VDO + IDrD

Attachments: These items are attached on the end of the report-- 1.Signed data sheet 2.Signed graph paper