1. ASSIGNMENT :
INSTRUMENTATION & MEASUREMENTS
To Design A Common Base Amplifier
Using Multisim:
Common Base Amplifier :
A common base amplifier is such an amplifier which has the following charecteristics:
High voltage gain but maximum current gain of 1
It has a voltage gain equal to 10 times of a common emitter amplifier
Has a high output impedance and low input impedance
Input is given at Emitter via coupling capacitor.
Output is capacitively coupled from collector.
Base is at ac ground..
There is no phase inversion from input to output & the output is apporximately the same
amplitude as input.
As the current gain is equal to 1 so the power gain is apporximately equal to voltage
gain.
Ap = Av

2. Simulated Circuit In Multisim:
Apparatus used:
Bode Ploter, Function Generator. Ground, Resistor, Capacitor, Inductor, connecting wires.
After connecting these I pressed ON button & get the output”

3. INPUT
WAVEFORM:
OUTPUT
WAVEFORM:

4. Designing A Band Pass Filter
FM 93.0 MHz:
A Band pass filter is a filter which accepts a specific band of frequency and rejecting all
other below and higher range of frequency.
Band pass filter is the combination of Resistor R, Capacitor C & inductor. It’s a reasonant
circuit/Tank Circuit.Thats why give a specific band.
Resonance Frequency:
As a series resonant circuit has the formula:
1/2f LC
For making filter of 93.0Mhz I calculated the values of capacitor & inductor using f=93.0Mhz.
C = 2.93 * 10-18
/L
Let L = 1uH
C = 2.93pF
R = 2kΩ
For the value of resistor I used the formula used for low , high pass , band pass and band stop
filters:
2
/R L C

5. Simulated Circuit:
Output:
It can be observed in following graph that the value of resonance frequency is 93.0MHz
which is nearly our required value.