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Laboratory Manual - King Fahd University of Petroleum and Minerals

Laboratory Manual - King Fahd University of Petroleum and Minerals

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''<br />

Where RL<br />

RC<br />

1<br />

// Rin2<br />

RC<br />

1<br />

// RB3<br />

// RB4<br />

//[ r 2<br />

( RL<br />

// RE2)(1<br />

)]<br />

<strong>and</strong><br />

RL<br />

// RE2<br />

(1 )<br />

A<br />

Buffer<br />

<br />

(5)<br />

r<br />

2<br />

RL<br />

// RE2<br />

(1 )<br />

2. Note that C 3 is associated with relatively small resistance <strong>and</strong> hence may significantly<br />

contribute to value <strong>of</strong> the low frequency pole particularly when R L is small:<br />

1<br />

1<br />

wL<br />

<br />

<br />

(6)<br />

r<br />

RS<br />

// RB<br />

1<br />

// RB2<br />

r<br />

2<br />

RC1<br />

// RB<br />

1<br />

// RB2<br />

CE<br />

( RE1 //<br />

) C3[(<br />

RE2<br />

//<br />

) RL<br />

]<br />

1<br />

<br />

1<br />

<br />

3. The high frequency pole can be expressed as:<br />

1<br />

1<br />

wH<br />

<br />

(7)<br />

''<br />

''<br />

[ C C (1 g R )] R // R C g R ( R // R )<br />

1 1<br />

m L in s 1<br />

m L in s<br />

'<br />

It can be seen that unlike R<br />

L<br />

, the value <strong>of</strong><br />

values.<br />

''<br />

R<br />

L<br />

will be almost constant for different load<br />

EQUIPMENTS & COMPONENTS<br />

1. Digital Oscilloscope, Bread Board, Digital Multi-Meter, Signal generator.<br />

2. DC supply V cc =5V from the Board.<br />

3. Two BJT 2N3904.<br />

4. Resistors: R sig =1k,R B1 =R B2 =30k, R B3 =R B4 =10k, R C1 =4.3k,R E1 =R E2 =1.3k,<br />

R L =100k <strong>and</strong> 1K.<br />

5. Capacitors: C E =47μF,C 1 =C 2 =C 3 =1μF.<br />

PRELAB WORK<br />

Students must perform the following calculations <strong>and</strong> SPICE before the lab.<br />

H<strong>and</strong> Calculation:<br />

1. Given that g m1 =g m2 =16.9mA/V <strong>and</strong> r π1 = r π2 =7.2kΩ, complete the Table I.<br />

R<br />

'<br />

''<br />

L<br />

R<br />

L<br />

R<br />

L<br />

1 kΩ<br />

100 kΩ<br />

% Change<br />

A Buffer<br />

2. For the two amplifier circuits shown in Figure 1 <strong>and</strong> Figure 2 calculate A M , f<br />

L<br />

, f , H<br />

BW <strong>and</strong> GB required to complete Table II.<br />

SPICE Simulation:<br />

3. Use the programs developed in the pervious SPICE tutorial to generate the required<br />

outputs for Figure 1 <strong>and</strong> Figure 2 to determine A M , f<br />

L<br />

, f<br />

H<br />

, BW <strong>and</strong> GB to complete<br />

Table II. For the SPICE analysis use the frequency range 10Hz to 8MHz. Use the BJT<br />

model given in the tutorial.<br />

24

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