Long Report 7

A) OB OBJE JECT CTIV IVES ES

The objective of this laboratory experiment is to design a cascaded amplifier using the operational amplifiers (Op-Amps).

INTRODUCTION

By combination of a fe Op-Amps! e can also change the magnitude of the input signal to the re"uired output. #uch combinations ill include an inverting amplifier in cascaded ith a noninverting amplifier or vice-versa so that the gain for each amplifier can be independently selected in order to obtain the overall gain. $n this experiment! the student can refer to all the Op-Amp circuits in %xperiment & as references for assembling the inverting and non-inverting amplifiers. As an example! an inverting amplifier cascaded ith a non-inverting amplifier is shon in 'igure .. 'or this circuit! the overall gain! * is given by * + * ,* ()

here * + o o/i /i + -0f/0i for inverting amplifier! *+ o/i+ o/i+ (10f/0i) (10f /0i) for non-inverting non-inve rting amplifier. amplif ier.

2ere! V i + V i is the input signal and

V o + V o is

the output signal of this cascaded amplifier.

Figure 7.1

B) PROCEDURE 1. Circuit Assembly

a. 3lace the op amp in the loer central portion of the protoboard. 3osition the notch so that pin  is at the top left . %nsure that each pin of the op-amp is inserted into a separate hole.

Figure 7.2: Positioning of Op-Amp on Protoboard b.

4easure using 544 and record the resistance of 0 # and 0 f  in Table .. Table 7.1: Measured Resistance  Nominal

 Actual

(Ω)

(Ω)

0 i

6

7.896

0 f   

6

7.8:;6  

0i

6

.88 poer supply voltages at 19 and ?9 ith respect to ground.

d.

Build the cascade amplifier shon in 'igure .;.

'igure .; e. Apply a  pea6-to-pea6  2@ sine ave as input  #. C) RESULTS

a. 0ecord the result of i! o in table . 0esistor 0i 0f 0i 0f

ominal ) Actual) 6 7.896  6 7.8:;6  6 .88alculationD *+ -0f/0i

*+ (10f/0i)

+ -6/6

+ (16/6)

+ -

+ 1 + 

Overall *ainD * + *E* + -E + -

i +  o + -E + -

5iscussionD By combination of a fe Op-Amps! e can also change the magnitude of the input signal to the re"uired output. #uch combinations ill include an inverting amplifier in cascaded ith a noninverting amplifier or vice-versa so that the gain for each amplifier can be independently selected in order to obtain the overall gain. As an example! an inverting amplifier cascaded ith a non-inverting amplifier is shon in 'igure .. 'or this circuit! the overall gain! * is given by * + * ,* ()

here * + o/i + -0f/0i for inverting amplifier! *+ o/i+ (10f/0i) for non-inverting amplifier.

2ere! V i + V i is the input signal and E) C"#clusi"#

V o + V o is

the output signal of this cascaded amplifier 

) Ce learn ho to design a cascaded amplifier using operational amplifiers. ) Ce learn ho to calculate the overall gain and o (output). ;) Ce learn ho to design a cascaded amplifier using FT#3$>%.

$) Discussi"# "# sust%i#%ble %&&lic%ti"# "' "&er%ti"#%l %m&li'ier

The operational amplifier is a complex device containing many components. Get! its terminal  behavior may be studied ithout understanding its complex circuitry. $n the operational amplifier circuits studied in this course! a circuit element is connected  beteen the output terminal and the inverting input. #uch an op amp circuit is said to have negative feedbac6. $f the op amp ith negative feedbac6 is operating in its linear region! then the assumptions of  +  and i + i + 7 may be made in circuit analysis.

The inverting amplifier! shon in 'igure &.;! ill have a gain of ith the output  being :7H out of phase ith respect to the input. 0 f  must be larger than 0 # to result in amplification of the input signal.

The output e"uation for an inverting amplifier isD

The output e"uation for a non-inverting amplifier isD

A&&e#(i *A+ List "' A,%il%ble Resist"rs i# t-e L%b

77 :7 7 ;;7 6 6 .6 .6 ;.;6