Semiconductor Labs, Simulation Track & Project Ladder

Hands-on learning path. A 25-lab sequence from material basics to failure analysis (diode forward/reverse, Zener, Schottky comparison, LED, photodiode, BJT input/output/β/Q-point, JFET, MOSFET transfer/output/switching, CMOS inverter, MOS C–V simulation, power MOSFET loss, IGBT comparison, solar cell, Hall sensor, temperature dependence, thermal measurement, SPICE modelling, parameter extraction, failure-analysis case study), each with objective, theory, equipment, schematic, procedure, expected results, measurements, graphs, calculations, safety, troubleshooting and questions; a simulation track (LTspice, ngspice, PSpice, QSPICE, KiCad, Python); and a project ladder from beginner to professional — with Python processing sample lab data (β table, Early voltage, diode temperature coefficient).

Semiconductor intuition comes from measuring real devices: seeing the diode knee move with temperature, the BJT's β vary with current, and the MOSFET's threshold shift. Labs make the equations concrete.

Every lab follows the same method: predict, simulate, build, measure, compare, explain — then level up through projects.

An analogy

The lab track is like learning a language through conversation: grammar books (theory) help, but fluency comes from speaking (measuring) and being corrected (comparing with prediction).

Lab method and safety

Predict (hand calculation), simulate (SPICE), build, measure with appropriate instruments and current limits, compare, explain. Safety: current-limit supplies, respect power ratings (small devices burn quickly), ESD precautions for MOSFETs, eye protection for power experiments and lasers, never touch charged capacitors, and let hot devices cool.

Simulation track

Tools and tasks:

Project ladder

Beginner: diode tester, LED characteristic analyser, Zener regulator, BJT and MOSFET switches, simple solar-cell analyser, temperature-dependent diode experiment. Intermediate: semiconductor curve tracer, BJT/MOSFET parameter analysers, LED driver, photodiode amplifier, Hall sensor interface, MOSFET thermal monitor, MPPT simulator. Advanced: automated characterisation system, SPICE diode model extractor, BJT/MOSFET extraction tools, device thermal analysis, power MOSFET loss calculator, SiC vs Si switching comparison, GaN switching simulation, reliability data analyser. Professional: automated I–V/C–V platform, characterisation dashboard, datasheet comparison engine, power-device selection system, failure-analysis workflow tool, multi-temperature characterisation, SPICE model extraction and validation platform.

Assessment

Each module's assessment mixes concept MCQs, numerical problems, diagram and characteristic-curve interpretation, device identification, datasheet questions, troubleshooting scenarios, simulation tasks and design challenges. Answers are revealed only after submission; labs are graded on method, data quality, analysis and explanation of deviations.

Formulas

Worked example: β

Given: I_B 25 µA, I_C 4.0 mA

Find: β.

Answer: 160

Worked example: Early voltage

Given: (2 V, 2.00 mA), (12 V, 2.20 mA)

Find: V_A.

Answer: 98 V

Worked example: Percent error

Given: Predicted 0.60 V, measured 0.62 V

Find: Error.

Answer: +3.3%

Lab sequence (25 labs)

  L1 materials & resistivity    L2 diode forward I–V      L3 diode reverse leakage
  L4 Zener breakdown             L5 Schottky vs PN          L6 LED I–V & light output
  L7 photodiode (PV & PC modes)  L8 BJT input/output curves L9 BJT β vs I_C
  L10 BJT Q-point & stability    L11 JFET characteristics   L12 MOSFET transfer curve
  L13 MOSFET output curves       L14 MOSFET switching       L15 CMOS inverter VTC
  L16 MOS C–V (simulation)       L17 power MOSFET losses    L18 IGBT vs MOSFET
  L19 solar-cell I–V & MPP       L20 Hall sensor            L21 temperature dependence
  L22 thermal measurement (θ)    L23 SPICE device modelling L24 parameter extraction
  L25 failure-analysis case study
  Each: objective · theory · equipment · components · schematic · procedure · expected result ·
        measurements · graph · calculations · safety · troubleshooting · questions · conclusion

The labs follow the course modules. Low-cost setups (SMU or bench supply + DMMs, an oscilloscope, a curve tracer or Arduino-based tracer, a thermal chamber substitute such as a hot plate with thermocouple) cover most of them; C–V and advanced labs can be simulation-based.

Processing lab data (sample measurements)

import math
# Lab data processing: BJT beta from a measured table and Early voltage from two output points (sample data)
table = [(10e-6, 1.52e-3), (20e-6, 3.10e-3), (50e-6, 7.60e-3), (100e-6, 14.2e-3)]   # (IB, IC) at VCE = 5 V
for ib, ic in table:
    print(f"IB = {ib*1e6:5.1f} uA: IC = {ic*1e3:5.2f} mA, beta = {ic/ib:.0f}")
(v1, i1), (v2, i2) = (2.0, 3.02e-3), (10.0, 3.26e-3)          # output points at IB = 20 uA
slope = (i2 - i1) / (v2 - v1)
VA = i1 / slope - v1
print(f"Early voltage from output slope: VA = {VA:.0f} V, ro = {1/slope/1e3:.0f} kohm")
vf = [(25, 0.652), (75, 0.548)]                                  # diode VF at 1 mA vs temperature
print(f"diode temperature coefficient: {(vf[1][1]-vf[0][1])/(vf[1][0]-vf[0][0])*1e3:.2f} mV/C")
# IB =  10.0 uA: IC =  1.52 mA, beta = 152
# IB =  20.0 uA: IC =  3.10 mA, beta = 155
# IB =  50.0 uA: IC =  7.60 mA, beta = 152
# IB = 100.0 uA: IC = 14.20 mA, beta = 142
# Early voltage from output slope: VA = 99 V, ro = 33 kohm
# diode temperature coefficient: -2.08 mV/C

From a sample BJT table, β is ~150 at low current and falls to 142 at 14 mA (high-injection onset). Two output points at I_B = 20 µA give V_A ≈ 99 V and r_o ≈ 33 kΩ. The diode's forward voltage at 1 mA falls 2.08 mV/°C — matching theory. Always compare such results with predictions and datasheet ranges and explain differences.

Common mistakes

Applications

Key takeaways

Going further