Quiz 2. Analog Signals

Question 1

______ stop the flow of current.

Answer 1

resistors

Question 2

______ need changing voltage to produce current

Answer 2

capacitors

Question 3

_______ need a changing current to produce a voltage

Answer 3

inductors

Question 4

Ohms Law?

Answer 4

I=V/R

Question 5

Kirchoff’s voltage law

Answer 5

sum of voltage sources and losses should equal zero in a circuit loop

Question 6

Krchoff’s current law

Answer 6

sum of current sources and losses should equal zero at a circuit junction (first law)

Question 7

Power.

give equation. and what number law is this?

Answer 7

P=VI=RI^2

Question 8

DC-resistor/capacitor:

rules to memorize

Answer 8

fully discharged capacitor is equivalent to short circuit

fully charged capacitor is equivalent to an open circuit

Question 9

Figure out:

In a RC circuit given, assume the capacitor is initially fully discharged.

What is the current and i and output voltage when:

1. the switch is first closed
2. at steady state (long time)
3. in between these two stages

Answer 9

(FIGURE THIS OUT)

Question 10

If a signal level is to low what can u use?

Answer 10

amplification

Question 11

_________ of the signal-Voltage or current or current to voltage

Answer 11

conversion

Question 12

_________ of a signal- conditioning non linear sensor output to be linear

Answer 12

linearization

Question 13

______ out noise based on frequency- small AC voltages superimposed onto signals which are typically AC or DC voltages

Answer 13

fitler

Question 14

___________-drain only a minimal amount of current from a measurement circuit with the measuring device

Answer 14

impedance matching

Question 15

what is analog filtering

Answer 15

it is a process which changes the relative amplitude of, or eliminates altogether, frequency components of a signal

Question 16

General information:

filtering can be though of as kind of frequency dependent attenuation, where the signal output of the filter will be attenuated (reduced) at a specified frequency range

Answer 16

General

Question 17

cut off frequency

Answer 17

• is used to describe the frequency where the filter begins to operate significantly on an incoming signal
• actual point is where output is attenuate by 3dB when compared to the input

Question 18

what are the basic types of frequency?

Answer 18

low-pass –> keep signals lower than fcl

high pass–> keep signals bigger than fch

band pass –> keep signals between fch and fcl

Question 19

the cutoff frequency describes

Answer 19

the frequency threshold after which higher frequencies are blocked

Question 20

if we add two similar filters we get a quicker frequency cut off. this is called a ___ order system.

although this may give better frequency cut off, the components need to be selected carefully to avoid overshoot in the time domain– recall the pendulum and spring

Answer 20

2nd order

Question 21

__________ is a high-gain dc
differential amplifier. It is basically an integrated circuit
chip with transistors. It has two inputs, negative terminal
v1 (some times called inverting input) and positive
terminal v2 (sometime called non-inverting input) and
one output v0. The effective input to the amplifier is the
voltage difference of the two inputs v1-v2.

Answer 21

Operational amplifier (OPAmp)

Question 22

current flow into the input of the op amp is zero

Answer 22

– almost true in FET op amps where input currents can
be < pA, but this is not always true in bipolar highspeed
op amps where tens of μA input currents are
found.

Question 23

Op amp gain is assumed to be infinite

Answer 23

Drives the output voltage to any value to satisfy the
input conditions.

– In reality, saturation occurs when the output voltage
comes close to a power supply rail, but reality does
not negate the assumption, it only bounds it.

Question 24

voltage follower is often used _____________________

Answer 24

for the construction of buffers for logic circuits

Question 25

input impedance of the op amp is very high, giving __________________________________

Answer 25

Input impedance of the op amp is very high,
giving effective isolation of the output from the
signal source. You draw very little power from
the signal source, avoiding “loading” effects. This
circuit is a useful first stage