Practical Electronics Circuit Design

Module 1 – Unit 1.1

Title: Introduction to Electronics Circuit Design
Lesson Description:
Defines electronic circuit design as the manipulation of current flow using components to achieve a desired result, using a football team analogy.
Practical:
Demonstrates the concept by constructing a basic circuit with a battery, switch, resistor, and LED to manually control the light.

Module 1 – Unit 1.2

Title: The Solderless Breadboard
Lesson Description:
Introduction to the solderless breadboard, explaining its internal connections and its use for prototyping circuits without damaging component leads.
Practical:
Demonstrates the construction of a simple LED circuit on a breadboard using jumper wires, a battery, a switch, and a resistor.

Module 1 – Unit 1.3

Title: Circuit Schematics and Component Symbols
Lesson Description:
Introduction to circuit schematics as diagrammatic representations of circuits using standardized symbols for electronic components.
Practical:
Demonstrates the use of component symbols by drawing the schematic diagram for a simple LED circuit and explaining its operation.

Module 1 – Unit 1.4

Title: Fundamental Electrical Concepts
Lesson Description:
Introduction to the basic concepts of electric charge, current, voltage, resistance, Ohm’s Law, and electrical power.
Practical:
Demonstrates Ohm’s Law by varying the voltage supplied to a fixed resistor and observing the proportional change in current, confirming the relationship V = I × R and the power formula P = V × I.

Module 1 – Unit 1.5

Title: The Multimeter
Lesson Description:
Introduction to the digital multimeter, its key components (display, selector knob, probe jacks), and the function of each setting for measuring different electronic parameters.
Practical:
Demonstrates how to correctly set up and use the multimeter to measure resistance, DC voltage, transistor gain, capacitance, DC current, and perform diode/continuity tests.

Module 1 – Unit 1.6

Title: Power Sources and Ground
Lesson Description:
Overview of the two main power sources for electronic circuits (AC mains and battery) and the definition of ground as the zero-volt reference point in a circuit.
Practical:
Demonstrates measuring AC mains voltage, a 9V battery, and the DC output of a switch-mode power supply, and confirms the negative terminal of a battery as the ground reference.

Module 2 – Unit 2.1

Title: Fundamental Circuit Design Rules
Lesson Description:
Introduces two key rules: current flows from a point of higher voltage to lower voltage, and more current flows through the path of least resistance.
Practical:
Demonstrates the first rule by measuring voltage drops at different points in a series LED circuit and the second rule by measuring current distribution across parallel branches with different resistances.

Module 2 – Unit 2.2

Title: Open, Closed, and Short Circuits
Lesson Description:
Defines the three fundamental circuit conditions: open circuit (incomplete path), closed circuit (complete path), and short circuit (direct connection between supply terminals).
Practical:
Demonstrates each condition using a simple LED circuit, showing how an opening stops current flow, a complete path allows it, and a direct bypass diverts current away from the load.

Module 3 – Unit 3.1

Title: Resistors
Lesson Description:
Introduction to resistors, covering fixed and variable types, color code identification, tolerance calculation, and series/parallel combinations.
Practical:
Demonstrates measuring resistor values with a multimeter to verify tolerance, confirming calculations for series, parallel, and series-parallel networks, and showing how increasing resistance reduces current flow in an LED circuit.

Module 3 – Unit 3.2

Title: Potentiometers
Lesson Description:
Introduction to the potentiometer, a three-terminal variable resistor used to manually adjust voltage or current in a circuit.
Practical:
Demonstrates how to measure the variable resistance of a potentiometer and uses it in circuits to adjust current to a load and control the brightness of an LED.

Module 3 – Unit 3.3

Title: Voltage and Current Divider Rules
Lesson Description:
Explanation of the voltage divider rule for series resistor networks and the current divider rule for parallel resistor networks, including their formulas and common applications.
Practical:
Demonstrates the calculation and measurement of voltage drop across a specific resistor in a series circuit and current through a specific branch in a parallel circuit to confirm the divider rules.

Module 3 – Unit 3.4

Title: Capacitors
Lesson Description:
Introduction to the capacitor, an electronic component that stores energy in an electric field, covering its construction, units, types, and behavior in DC and AC circuits.
Practical:
Demonstrates capacitor value identification, series/parallel combinations, the RC time constant during charging, and the component’s ability to block DC while passing AC.

Module 3 – Unit 3.5

Title: Inductors
Lesson Description:
Introduction to the inductor, an electronic component that stores energy in a magnetic field, explaining its behavior in DC and AC circuits.
Practical:
Demonstrates how to measure inductance with an LCR meter, visualizes the voltage spike across an inductor during switching, and shows how increasing AC frequency reduces current flow through the inductor.

Module 3 – Unit 3.6

Title: Capacitive and Inductive Reactance
Lesson Description:
Explanation of capacitive and inductive reactance, defining them as the frequency-dependent opposition to current flow introduced by capacitors and inductors in a circuit.
Practical:
Demonstrates the waveforms of direct and alternating current on an oscilloscope and uses an LCR meter to measure and verify the capacitive and inductive reactance values of components.

Module 3 – Unit 3.7

Title: Transformers and Relays
Lesson Description:
Introduction to the transformer, covering its operating principle, turns ratio calculations, and types, followed by an overview of the electromechanical relay and its switching operation.
Practical:
Demonstrates how to measure the output voltage of a center-tapped transformer and uses a low-voltage DC supply to energize a relay for switching a high-voltage AC load.

Module 3 – Unit 3.8

Title: Diodes
Lesson Description:
Introduction to the diode, a two-terminal semiconductor device that allows current to flow in only one direction, covering its biasing, characteristics, and key properties.
Practical:
Demonstrates forward and reverse bias using a rectifier diode, testing diodes with a multimeter, and the voltage-regulating behavior of a zener diode.

Module 3 – Unit 3.9

Title: Transistors
Lesson Description:
Introduction to the bipolar junction transistor (BJT), including types (NPN/PNP), biasing requirements, the DC load line, and its operation as a switch or amplifier.
Practical:
Demonstrates transistor biasing to determine cutoff, active, and saturation regions, and constructs a basic transistor switch circuit to control an LED.

Module 3 – Unit 3.10

Title: Thyristors, Triacs, and Diacs
Lesson Description:
Introduction to thyristors, triacs, and diacs as semiconductor switches, detailing their triggering requirements, current flow direction, and operational modes.
Practical:
Demonstrates the three operating modes of a thyristor (forward blocking, forward conducting, reverse blocking) and the four modes of a triac, followed by a demonstration of a diac’s breakover voltage.

Module 4 – Unit 4.1

Title: Visitor Guide System
Lesson Description:
Design and construction of a circuit that allows a room occupant to set a status (Hold On, Busy, Away) which is visually displayed to a visitor upon pressing an external button, with an audible alert for the “Hold On” status.
Practical:
Demonstrates the completed circuit using a breadboard, battery, push button, three SPST switches, three LEDs with resistors, and a buzzer, showing the correct visual and audible feedback for each selected status.

Module 4 – Unit 4.2

Title: Dark-Activated Lighting Circuit
Lesson Description:
Design of a circuit that uses a Light Dependent Resistor (LDR) to automatically turn on an LED in darkness and turn it off in light.
Practical:
Demonstrates the completed circuit on a breadboard, showing the LDR’s resistance change with light and the LED turning on when the sensor is covered (simulating darkness).

Module 4 – Unit 4.3

Title: Over-Voltage Protection (Crowbar) Circuit
Lesson Description:
Design of a crowbar circuit that protects a load by using a zener diode and thyristor to short the supply and blow a fuse when the input voltage exceeds a preset threshold.
Practical:
Demonstrates the completed circuit, showing an LED indicator on while the voltage is below the 5.8V threshold and turning off immediately when the voltage is increased past this point.

Module 4 – Unit 4.4

Title: Linear 5V DC Power Supply
Lesson Description:
Design of a linear power supply that steps down 220V AC mains, rectifies it to DC, filters it, and regulates it to a stable 5V DC output capable of delivering 100mA.
Practical:
Demonstrates the completed circuit using a transformer, bridge rectifier, filter capacitors, and a 7805 voltage regulator, showing a stable 5V DC output and an active power indicator LED.

Additional topics and projects will be added progressively