4.1 Semiconductions - Integrated Circuits

Question 1

what are integrated circuits?

Answer 1

arrangements of several electronic components in a common housing

Question 2

what are the advantages and disadvantages of IC?

Answer 2

Ad:
very high density
very compact
resistant to mechanical stress

Dis:
requires additional cooling
can’t be repaired

Question 3

what components are usually found on an IC?

Answer 3

Semiconductors
resistors
capicitors

Question 4

which amplifier is always in the input stage?

Answer 4

Differential amplifier

Question 5

what amp is usually in the output stage?

Answer 5

push-pull power amp

Question 6

in operational amplifiers, how are the inputs designated?

Answer 6

inverting input designated - sign
non-inverting input designated + sign

Question 7

in operation amplifiers, where is the output voltage measured?

Answer 7

between the output terminal and the common terminal

Question 8

in operation amplifiers, what signals can they amplify?

Answer 8

both AC and DC

Question 9

what is an ideal operational amplifier? (4)

Answer 9

-infinite amplification
-infinite input resistance
-input voltage bordering on zero
-small output resistance

Question 10

in operation amplifiers, what are the voltages of the positive and negatives?

Answer 10

+/- 5 to 18v

Question 11

in operation amplifiers, what is the result if the differential input voltage is positive?

Answer 11

negative output voltage

Question 12

in operation amplifiers, what is the result if the differential input voltage is negative?

Answer 12

positive output voltage

Question 13

what is a circuit with more than one op amp on a chip called?

Answer 13

Monolithically integrated analogue circuit

Question 14

in operation amplifiers, what is the benefits of a Monolithically integrated analogue circuit? (4)

Answer 14

-minimum space requirements
-high reliability
-small characteristic variance
-low manufacturing costs

Question 15

where are op amps extensively used?

Answer 15

-signal conditioning
-filtering
-mathematical operations

Question 16

what are operational amplifiers designed to do?

Answer 16

a voltage amplifying device to be used with external feedback components to perform a variety of operations

dependent on which feedback component (resistor, capacitor or both)

Question 17

what is amplifiers gain?

Answer 17

an op amps output signal

Question 18

what are the classifications of op amps gain? (4)

Answer 18

voltage = voltage ‘in’ and voltage ‘out’
current = current ‘in’ and current ‘out’
transconductance = voltage ‘in’ and current ‘out’
transresistance = current ‘in’ and voltage ‘out’

Question 19

in operational amplifiers, what is the output voltage signal equal to?

Answer 19

the difference between signals applied at its 2 inputs

Question 20

in operational amplifiers, what should the output do if an identical common signal is detected?

Answer 20

it should ignore the signal and there should be no change of the output

Question 21

in operational amplifiers, what is used for them to have very precise gain characteristics?

Answer 21

some form of negative feedback

Question 22

in operational amplifiers, what is differential input voltage?

Answer 22

where it responds only to the difference between the voltages on its input terminals

Question 23

in op amps, what is the ideal of open loop gain?

Answer 23

infinite

Question 24

in op amps, what is open loop gain?

Answer 24

gain of the op-amp without positive or negative feedback

Question 25

in op amps, what is the ideal for input impedance?

Answer 25

infinite

Question 26

in op amps, what is input impedance?

Answer 26

ratio of input voltage to input current

Question 27

in op amps, what is the ideal of output impedance?

Answer 27

zero

Question 28

in op amps, what is the ideal for bandwidth?

Answer 28

infinite

Question 29

in op amps, what is the ideal for offset voltage?

Answer 29

zero

Question 30

in op amps, what is op amps bandwidth?

Answer 30

the frequency range over which voltage gain of the amplifier is above 70.7% or -3dB of max output

Question 31

in op amps, at the detriment of high gain, but the gain of control of an op amp, what component is used to do this? and what is this called?

Answer 31

a suitable resistor across the amp from the output terminal to the inverting input negative feedback

Question 32

in op amps, how is negative feedback achieved? what is does this produce?

Answer 32

by feeding back a fraction of the output signal onto the input signal on the negative "inverting input" terminal. a closed loop circuit

Question 33

in op amps, what is effected through a closed loop circuit using negative feedback?

Answer 33

reduction of the amplifiers gain

Question 34

what is summing point?

Answer 34

the total of original input signal and any feedback signals provided by the output

Question 35

in inverting op amps, what are the two very important rules that they follow?

Answer 35

1. no current flows into the input terminals 2. v1 always equals v2

Question 36

what does the negative sign mean in the closed loop voltage gain equation?

Answer 36

output signal being 180 degrees out of phase due feedback negative in value

Question 37

what is the construction of non-inverting op amp?

Answer 37

output voltage connected to the inverting "negative" terminal producing negative feedback. input voltage connected directly to non-inverting terminal. output gain positive

Question 38

what are the benefits of a non-inverting op amp in a closed loop config? (3)

Answer 38

-very good stability -very high input impedance -low output impedance

Question 39

for overall closed loop gain, what will the value be?

Answer 39

always greater but never less than 1 positive determined by the ratio of the values of Rf and R2

Question 40

for overall closed loop gain, what will the value be if the Rf is zero?

Answer 40

exactly equal to 1

Question 41

for overall closed loop gain, what will the value be if R2 is zero?

Answer 41

gain will approach inifity

Question 42

how are amplifiers secured to protect them?

Answer 42

that neither a short circuit to ground, or short circuit to positive or negative terminals will destory the amplifier

Question 43

what must a user do to op amps due to their sensitivity to high voltages?

Answer 43

compensate for asymmetry by external wiring

Question 44

what is offset voltage?

Answer 44

the voltage required at the input terminals in order to set the output voltage to zero

Question 45

at what voltage in the input terminals create a voltage at the output terminal?

Answer 45

potential of zero

Question 46

what affects offset voltage compensation? (2)

Answer 46

-the amplifier used -how they're wired

Question 47

in offset voltage compensation, how is a compensation voltage applied in a 709 series?

Answer 47

to the input terminal where there is no input voltage

Question 48

in offset voltage compensation, how is a compensation voltage applied in a 741 series?

Answer 48

by a 10 kilo ohm potentiometer leaving input terminal free

Question 49

in offset voltage compensation, how is a compensation voltage applied in a 748 series?

Answer 49

high-ohmic network leaving both input terminals free