BME 322 Quiz 2 Week 4

Question 1

What is an amplifer?

Answer 1

Voltage Gain = Output Voltage / Input Voltage

Question 2

What is power gain equation

Answer 2

p = v^2/R = i^2R

Question 3

What is Decibels

Answer 3

dB = 10log(Pout/Pin)

10 dB represnts a power ratio of 10

Question 4

Compute the gain of

• log2 = 0.3
• given that Pin = 1w and Pout = 10w

Answer 4

1. 6dB
2. 10 dBw

Question 5

Operational amplifiter (op-amp)

Answer 5

Functional Configuration examples:
- Addition
- Multiplication
- Differentition
- Integration
- Analog-to-digital conversion
- Comparator
- Filter

We aren’t concerned with its internal operation, only with function configurations

Question 6

Properties of the Ideal op-amp

Answer 6

1. Infinite gian for open loop
2. Infinite input resistance
3. Zero output resistance
4. Infinite bandwidth

Question 7

Bandwidth

Answer 7

Question 8

Circuits with op-amp (what are the 2 rules)

Answer 8

1. Currents into both input terminals are zero [ i_in = 0]
2. Voltage difference between input terminals is zero [ V+ = V-]

Question 9

Voltage follower

Answer 9

• Very often used as buffer amplifier
• Isolate on circuit from its load
• Vout = Vin

Question 10

Electical Isolation iwth Isolation Amplifiers

Answer 10

• Isolation ampifiers break the ohmic continuity of electric signals between the input and output of the amplifier
• Isolation amplifiers use different supply-voltage sources and different grounds on each side of the isolation barrier
• Consists of an instrumentation amplifier at the input followed by a untiy-gain stage
• Very high impedance across isolation barrier modeled by isoaltion capacitance and resistance

Question 11

Difference / Differential Amplifiers Applications

Answer 11

1. Strain gauge bridge
   a. 2 pairs of strain gauge feeing the difference amplifiers (one pair is shortened another is lengthened)
2. ECG lead feeding a differential amplifier (ex: instrumentation amplifier)