COMSATS UNIVERSITY

Electronics -1

Lab # 9

Ahmad Hassaan
Name

Fa18-bee-230
Registration Number

Instructor’s Name Khurram Shahzad

In lab task 1:

For input voltage;

First, find re;

re=26mv/Ie

Ie=-0.0005051

re=26mv/-0.0005051

re = -51.4749

Neglecting minus sign;

re = 51.4749

Put value of re in Vi formula;

Vinput=Ie*re

=-0.0005051*51.4749

=-0.0259

Or
Vinput=-0.026

The value of Rb is also in range of given parameters.

Now for the output voltage at the load end

Vout= -51.68mV

Now the formula for gain is,

AVL=vout/ vin

Gain = -51.68/-25.9mv

=1.99
 V(vout)-V(vin)
180°

150°

120°
phase difference of vout and vin
90°

this difference has been taken over frequencies ranging from 1-4k
60°

30°

0°

-30°

-60°
1.0076584KHz,-112.38997°

-90°

-120°

-150°

-180°
V(vout) V(vin)
-16dB

-24dB

-32dB

-40dB

-48dB

-56dB

-64dB

-72dB

-80dB

-88dB

-96dB
1Hz 10Hz 100Hz 1KHz
--- E:\HASSAAN\5th sem uni\electronics 1\lab\Draft2.asc ---
 V3
V2

10
-2
R5
R4
R1 10k
2.7k
1k
R3

{R} C1
2N3904

V1
1µ
Q1

R6
AC -0.22 R2
.step param R 1 100 1 20k
100

.ac lin 10 1 100

--- E:\HASSAAN\5th sem uni\ECA-2\lab\lab 12\Draft3.asc ---

 V3
vinput
V2

10
-2
R5
R4
R1 10k
2.7k
1k

C1 C2
2N3904

ve vc voutput
V1
1µ 1µ
Q1

R6
AC -0.22 R2
20k
100

.ac lin 10 1 100

--- E:\HASSAAN\5th sem uni\ECA-2\lab\lab 12\Draft3.asc ---

 V3
vinput
V2

10
-2
R5
R4
R1 10k
2200k
1k

C1
2N3904

ve vc voutput
V1
1µ
Q1

R6
AC -0.22 R2
20k
100

.ac lin 10 1 100

--- E:\HASSAAN\5th sem uni\ECA-2\lab\lab 12\Draft3.asc ---

 V3
vinput
V2

10
-2
R5
R4
R1 10k
2.7k
1k

C1 C2
2N3904

ve vc voutput
V1
1µ 1µ
Q1

R6
AC -0.22 R2
20k
100

.ac lin 10 1 100

--- E:\HASSAAN\5th sem uni\ECA-2\lab\lab 12\Draft3.asc ---

Now for input impedance

Zi=r1 || r2 || beta*re

R1=1k

R2= 100

re=-51.4749

zi =31.036
now for section 2:

when RE is open

Voltages Measured
VOUT 591.260u

VC 593.101u

VE 683.83u

when C2 section is shorted:

Voltages Measured
VOUT 603.81uV

VC 0v

VE 700uV

when C2 section is open:

Voltages Measured
VOUT 0v

VC 0v

VE 16.784m

Critical analysis:
We have learnt how to verify the AC and DC parameters of the common base amplifier. We have learnt
how the circuit functions when different parameters of the circuit have been cut and have been left
either short or open.