Page 1 of 5
Dated: _____________
Section: _____________
EE-216 ELECTRONICS – I
LABORATORY EXERCISE – 9
BJT Common Emitter Frequency Response
GROUP: ______________
Names
Reg. no.
Report Marks / 10
Viva Marks / 5
docsity.com
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
BJT Common Emitter Frequency Response-Basic Electronics-Lab Assignment, Exercises of Electronics
The course gives the students a sound knowledge of Fourier transforms along with Fourier integrals, partial differential equations, advanced vector analysis, complex variables and complex integrals. This lab includes: BJT, Common, Emitter, Frequency, Response, Simulation, Variations, Capacitances, Bias, Point, Parameters, Sweep, Analysis
Typology: Exercises
2011/2012
1 / 5
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download BJT Common Emitter Frequency Response-Basic Electronics-Lab Assignment and more Exercises Electronics in PDF only on Docsity!
Page 1 of 5
Dated: _____________
Section: _____________
EE-216 ELECTRONICS – I
LABORATORY EXERCISE – 9
BJT Common Emitter Frequency Response
GROUP: ______________
Names Reg. no. Report Marks / 10 Viva Marks / 5
Page 2 of 5
Frequency Response Common Emitter Amplifier
Introduction
- This laboratory execise is meant to enble the students to experiment with simulation of the frequency response of a Common Emitter (CE) BJT amplifier and study the effect of variations circuit capacitances on the frequency response of the amplifier. The effect of variations of internal capacitances (simulated internal capacitances) on the CE amplifier frequency response is also studied.
Objective
- This laboratory will enable the students to achieve the following: 2.1. Calculate the bias point and the amplifier parameters like Rin, Av, Gv, Rou t etc. 2.2. To analyze the frequency response of a Common-Emitter (CE) amplifier. 2.3. To use AC Sweep analysis simulation and obtain the Gain and phase frequency response curves_._
Conduct of Lab
- The student have to perform this experiment using Pspice.
- The students are required to work in groups of three to four; each student must attempt to understand the the use of a simple set up for measuring the parameters of the given transistor.
- In case some aspect of the lab experiment is not understood the students are advised to seek help from the teacher, the lab technicians or the assigned Teaching Assistant (TA).
Theory and Background.
- The students are referred to class lecture notes for the theory of the BJT Common Emitter Amplifier. This experiment is designed to understand the effect of different capacitances on the frequency response of the amplifier. Initially brief DC Analysis is performed in order to determine the Q point of the amplifier. The frequency response of the amplifier is afterwards studied.
Fig. 1: Common-Emitter amplifier (with input divider)
- DC Analysis a) For a 2 mA of collector current Ic , What is the VC of transistor?
𝑂𝑈𝑇
Page 4 of 5
c) Now set the value of CC1 back to 1μF and increment the value of CC2 capacitor by a multiple factor of
- What is the low cut-off frequency?
The low cut-off frequency of the Amplifier f C2 is _____________________
d) Set the value of CC2 back to 1μF and now increment the value of CE capacitor by a multiple factor of
- What is the low cut-off frequency?
The low cut-off frequency of the Amplifier f C3 is _____________________
e) On the basis of above finding, explain which capacitance has the most dominating effect on the low cut-off frequency. Support your answer with reasoning.
3. High Frequency Response a) The high frequency response of the amplifier is greatly influenced by the internal capacitances within the transistor, namely Cμ and Cπ. In order to observer and determine the most dominating capacitance, the two external capacitors Cmeu and Cpi are included in the circuit to give an equivalent effect of the Base-Collector and Base-Emitter capacitance. So the first task would be to calculate the frequency response of the amplifier with modified transistor. This will be followed by the Frequency plot of the amplifier obtained by simulation using the previous SIMULATION PROFILE. Subsequently one value of capacitor will be changed one at a time to observe which capacitor has the most dominating effect on high frequencies.
Fig. 2: Common-Emitter amplifier-modified to study internal capacitance effect
b) Find the high frequency response of common emitter amplifier (Fig. 2). Calculate the high cut off frequency of the amplifier using the value of Cmeu and Cpi? Save your results.
Calculated High Frequency Cut-off f CHcalculated __________________________________
c) Measure the high frequency response of common emitter amplifier (Fig. 2). From the plot? Save your results.
Measured High Frequency Cut-off f CHmeasured __________________________________
Page 5 of 5
d) Increment the value of capacitor Cmeu by a factor of 10 and report the high cut-off frequency of amplifier.
The new high cut-off frequency of the Amplifier fCH1 is _____________________
e) Set the value of capacitor Cmeu back to 1pF and now increment the capacitor Cpi by a factor of 8 and report the high cut-off frequency of amplifier.
The new high cut-off frequency of the Amplifier now is fCH2 is _____________________
f) Report which capacitance has the greater effect on the high cut-off frequency of the amplifier? Explain your answer with reasoning.
Lab Report:
Each student group has to submit detailed lab report with proper outputs and results obtained by performing
experiment. This handout will form part of the submitted report and along with all the detailed calculations
attached in typed form, the various graphs and the explanation also be included with report. Your lab report is
due before the next lab.