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Xavier University

College of Engineering

Electronics and Communication Department

Experiment No.3

Diode Load Line

Date Performed : Jan. 5, 2011 Subject: ACE04L

Date Submitted : Jan 12, 2011 Group Number:

Group Leader: Oliver Orville Oliveros

Group Members:Belitor, Jonas-Noe P.

Siose, Reuven Kerr

Waminal, Archie

Presentation:Data and results:

Analysis and Conclusion:

Total:

Instructor:

Instructors Signature:

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I. Objective

II. Introductory Information

A load line is used in graphic analysis of circuits, representing the constraint other

parts of the circuit place on a non-linear device, like a diode or transistor. A load line

represents the response of a linear circuit connected to the nonlinear device in question.The operating point is where the parameters of the nonlinear device and the parameters of

the linear circuit match, according to how they are connected while still adhering to their

internal systems.In the example on the right, the nonlinear diode is placed in series with a linear

circuit consisting of a resistor and a voltage source. The load line represents the

relationship between current and voltage in the linear part of the circuit while the

exponential represents the relationship between current and voltage in the nonlineardevice. Since the current going through three elements in series should be the same, the

operating point of the circuit will be at the intersection of the exponential with the load

line.

In a BJT circuit, the BJT has a different current-voltage(IC-VCE) characteristicdepending on the Base current. Placing a series of these curves on the graph shows how

the base current will affect the operating point of the circuit.The load line is used for dc analysis, and has no bearing on small-signal

analysis once an operating point is identified.

III. Materials Needed

Module EL-1-B, Two Multimeters.

IV. Procedure

. For Diode D construct a current-voltage graph. Limit the current to 10mA and use a fullsheet of graph paper for an enlarge scale. Set resistor R to 1000 ohms and VB to 10 volts

and connect the diode and resistor, R, in series (if necessary by-pass the input

potentiometer). Measure and record VQ and IQ. From a load line on your graph comparethese values of VQ and IQ with the experimental results. Repeat for R = 2000ohms and R

= 4000ohms.

2. Repeat step 1 for zener Diode ZD2. bypass the series resistor connected to this zener

diode.. Repeat step 1 foe LED. Bypass the series resistor connected to this LED.

Data and Results

Table 1. For diode D

Resistance VQ IQ measuresd IQ load line % Diff. for IQ1000 3.52 V 10.51mA 3. 52mA 66.50

2000 4.92V 6.5mA 2.46 mA 62.15

4000 5.51V 3.82mA 1.377 mA 63.95

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Table 2. For Zener Diode D2

Resistance VQ IQ measuresd IQ load line % Diff. for IQ1000 3.16 V 4.95mA 3.16 mA 36.16

2000 4.63V 2.54mA 2.315 mA 8.854000 4.614V 2.08mA 1.153 mA 44.56

Table 3. For LED

Resistance VQ IQ measuresd IQ load line % Diff. for IQ1000 3.193 V 8.56mA 3.193 mA 62.69

2000 3.21V 5.13mA 1.605 mA 68.71

4000 5.53V 2.24mA 1.3825 mA 38.28