ECEUH
ECE 3355 · ECE 3155 · Electronics

Electronics, one circuit at a time.

Worked homework and a lab where the circuit is the explanation. Turn each schematic, or each pole-zero stack, in 3D, watch which parts the step is about, and read the voltages, currents and responses that the equations predict.

Homework 1

Amplifier models

Ten dependent-source amplifier models, parts (a) to (j). For each one, the voltage gain, input resistance and output resistance, derived from the symbols; any numbers come from exploration values you set.

Open Homework 1
  1. aReversed control voltage, current source back toward the input
  2. bControl voltage across a gap that includes R₂
  3. cControl voltage between input and output
  4. dCurrent-controlled current source boosting the output node
  5. eInverted dependent voltage source
  6. fControl voltage across one of two series resistors
  7. gDependent current returned through the input's ground leg
  8. hReversed control across one resistor of a three-resistor string
  9. iTwo dependent voltage sources with output feedback
  10. jFeed-forward current source in parallel with R₂

Homework 2

Amplifiers

Loading at both ports, cascades and their order, a minimum-stage design, transconductance, dependent-source circuits, a block cascade, and the hybrid-π model with emitter resistance. Problems A1 to A9 with every subpart.

Open Homework 2
  1. A1Loading at both ports of a voltage amplifier
  2. A2Loaded gain, power gain and an output-current limit
  3. A3Three-stage cascade and the swapped order
  4. A4SABL or SBAL: choosing the cascade order
  5. A5Minimum-stage design with a 10 mV signal floor
  6. A6Transconductance amplifier between source and load
  7. A7Left: grounded current source controlled across the input-output gap
  8. A7Right: two current-controlled current sources
  9. A8Cascade of three two-port blocks with crossed ports
  10. A9Hybrid-π model with emitter resistance

Homework 3

Frequency response

Bode magnitude and phase from the supplied transfer functions, shown as a 3D stack of their poles and zeros, then two-stage corners and bandwidth, loaded and buffered RC circuits, a compensated probe, and a biased nonlinear amplifier.

Open Homework 3
  1. P1Origin zero, one finite zero, three poles
  2. P2Double pole at 20,000 rad/s
  3. P3Negative gain with an origin zero
  4. P4Double zero at 300 rad/s with negative gain
  5. P5Low-pass input, high-pass output, and the bandwidth
  6. P6Three RC circuits: buffered, loaded, and current-controlled
  7. P7Compensated 10:1 oscilloscope probe
  8. P8Piecewise transfer characteristic with DC bias

Homework 5

Op-amps

Inverting and non-inverting amplifiers, summers, potentiometer gain control, current regulators, and RC circuits with Bode and pole-zero plots. Problem 5 is blank in the handout and is marked as such.

Open Homework 5
  1. 1Four inverting amplifiers: gain and Rin
  2. 2Non-inverting amplifier: v1, v2, i2
  3. 3Loaded non-inverting amplifier and i4
  4. 4Every node and branch, and the extra current
  5. 5Blank in the handout
  6. 6T-network current regulator
  7. 7Gain range with a loaded potentiometer
  8. 8Op-amp voltmeter with a moving-coil meter
  9. 9Design a weighted summer
  10. 10Attenuator then non-inverting gain
  11. 11Potentiometer gain control, capped at 11
  12. 12Adjustable voltage from a buffered pot
  13. 13Two circuits with floating outputs
  14. 14RC amplifier and its Bode plot
  15. 15Poles and zeros with C1, R1, L1
  16. 16Design: 0 dB low, 20 dB high
  17. 17Floating source into a bridge

Homework 6

Op-amps II

Difference and instrumentation amplifiers, common-mode range, positive feedback, output limits, and an open-loop comparator. Fifteen problems, each with its own circuit.

Open Homework 6
  1. 1Difference amplifier: gain, Rid, mismatch, CMRR
  2. 2Equal-resistor difference amplifier and its input resistances
  3. 3Input common-mode resistance
  4. 4Common-mode range, and widening it
  5. 5Positive feedback for high gain
  6. 6Variable gain with RG
  7. 7INA105 module: six amplifiers from one part
  8. 8Instrumentation amplifier with a 100 kΩ pot
  9. 9Bridge output for floating loads
  10. 10Largest input before clipping
  11. 11Voltage and current limits, inverting
  12. 12Load current set by vIN and RL
  13. 13Voltage and current limits, non-inverting
  14. 14Two coupled op amps, output across R4
  15. 15Inverting amplifier beside a comparator

Lab · ECE 3155 Experiment II

Operational amplifiers

Inverting, summing, noninverting and unity-gain amplifiers, the Part E design tested with +5 V, +15 V and −15 V, and the three questions: seventeen activities and the six measurement tables. Predictions and example parts are labelled; the tables are for your own readings.

Open the lab
  1. A1Design the inverting amplifier
  2. A2Construct it: pins, supplies, bypass capacitors
  3. A3Drive it at 1 kHz and sketch both traces
  4. A4Measure vG, vOUT and v− (Table 1)
  5. A5Currents in Ri and Rf (Table 2)
  6. A6Measured gain and percent error
  7. A7Maximum expected error
  8. B1Design the two-input summer
  9. B2Build, measure, compare (Tables 3 and 4)
  10. C1Design the noninverting amplifier
  11. C2Waveforms and voltages (Table 5)
  12. D1Unity-gain amplifier (Table 6)
  13. EDesign vOUT = 0.1vIN1 + 0.2vIN2 − 0.3vIN3
  14. E1Test with +5 V, +15 V and −15 V
  15. Q1Input resistance of the inverter
  16. Q2What Table 2 says about the input
  17. Q3v− and v+ in the noninverting amplifier

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