Electronics Lab Projects

Analog Circuit Design · SPICE Simulation · Semiconductor Devices

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Overview

This repository contains LTspice circuit simulation projects from the Electronics Lab course at HAW Hamburg. The experiments cover fundamental analog semiconductor devices and circuits — from MOSFET characterization and BJT amplifier design to operational amplifiers and 555 timer applications.

Each .asc file is an LTspice schematic ready to simulate.

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Repository Structure

electonics2projects/
│
├── MOSFET/                        # MOSFET characterization & applications
│   ├── MOSFET.asc                 # MOSFET Id/Vgs curves, threshold voltage, transconductance
│   └── MOSFETasSwitchAndAmplifier.asc   # MOSFET as switch and single-ended amplifier
│
├── BJT_Transistor/                # Bipolar Junction Transistor (BJT) circuits
│   ├── transistorCkt.asc          # BC546A output & transfer characteristics
│   └── CommonEmitterCircuit.asc   # Common emitter amplifier — gain, Rin, Rout
│
├── Amplifiers/                    # Operational & differential amplifiers
│   ├── OperationalAmplifier.asc   # Op-amp input/output characteristics
│   └── DifferentialAmplifier.asc  # Differential amplifier — CMRR & optimization
│
└── Timer555/                      # NE555 timer circuit configurations
    ├── Timer555ForAstableOperation.asc    # Astable mode — free-running oscillator
    └── Timer555ForMonostableOperation.asc # Monostable mode — one-shot pulse

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Experiments

MOSFET — Characterization & Applications

File	Description
MOSFET.asc	Sweeps gate voltage to plot Id/Vgs curves. Extracts threshold voltage (Vth) and transconductance coefficient (k). Verifies current mirror behavior (I1 = I2).
MOSFETasSwitchAndAmplifier.asc	Demonstrates MOSFET operating in switch and amplifier regions. Defines input/output characteristics for single-ended amplifier configuration.

Concepts: Transfer characteristics · Threshold voltage · Transconductance · Current mirror · Saturation vs. triode region

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BJT Transistor — BC546A

File	Description
transistorCkt.asc	Plots output and transfer characteristics of BC546A NPN transistor. Graphically determines transconductance at a defined operating point.
CommonEmitterCircuit.asc	Common emitter amplifier. Measures DC operating point, AC voltage gain, and input/output resistance using the half-voltage method.

Concepts: Ic/Vce output characteristics · Transfer curve · Q-point biasing · AC gain · Half-voltage resistance measurement

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Amplifiers — Op-Amp & Differential

File	Description
OperationalAmplifier.asc	Analyzes op-amp input/output behavior. Characterizes gain, bandwidth, and operating limits.
DifferentialAmplifier.asc	Implements a differential amplifier from literature specifications. Investigates CMRR and circuit optimization techniques.

Concepts: Open-loop vs. closed-loop gain · CMRR · Differential vs. common-mode signals · Circuit optimization

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NE555 Timer — Astable & Monostable

File	Description
Timer555ForAstableOperation.asc	Free-running oscillator configuration. Frequency and duty cycle set by R/C network.
Timer555ForMonostableOperation.asc	One-shot pulse generator. Pulse width determined by R/C time constant.

Concepts: RC time constant · Duty cycle · Trigger/threshold behavior · Oscilloscope waveform analysis

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Tools

Tool	Purpose
LTspice	Schematic entry & SPICE simulation (.asc files)
Oscilloscope	Hardware waveform measurement and validation
Multimeter	DC operating point verification

Running a Simulation

1. Open any .asc file in LTspice
2. Press Run (F5) to start the SPICE simulation
3. Probe signals by clicking on nets or components
4. Use .op, .dc, .ac, or .tran directives already configured in each schematic

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Author

Mainuddin Monsur Robin M.Sc. Information and Communication Engineering — HAW Hamburg