Practical Electronics from Scratch: The Visual Guide

Unit 1: Start Safely and Understand Electricity

1. Know Your Limits: Low-Voltage Work Only
2. Set Up a Safe Workbench
3. Disconnect Power and Check for Stored Energy
4. Voltage: Measure the Difference Between Two Points
5. Current: Follow the Complete Path
6. Resistance: Understand What Limits Current
7. Read Electrical Units and Prefixes
8. Tell DC, AC, Polarity, and Circuit Common Apart

Unit 2: Read Circuits and Predict What They Do

1. Read Common Schematic Symbols
2. Trace Nodes, Junctions, and Return Paths
3. Use Ohm's Law to Find Voltage, Current, or Resistance
4. Calculate Power and Check Component Ratings
5. Series Circuits: Share Voltage Along One Path
6. Parallel Circuits: Split Current Between Branches
7. Voltage Dividers: Predict the Effect of a Load
8. Recognize Open Circuits, Short Circuits, and Overloads

Unit 3: Use Your Multimeter with Confidence

1. Identify Meter Functions, Input Jacks, and Lead Limits
2. Choose a Range and Read the Display
3. Measure DC Voltage Across Two Points
4. Measure Resistance with Power Disconnected
5. Use Continuity Mode to Check a Path
6. Use Diode Mode and Understand Its Limits
7. Measure Current in Series and Return the Lead to the Voltage Jack
8. Check Unexpected Readings Before You Trust Them

Unit 4: Identify and Use Common Components

1. Match Physical Parts to Schematic Reference Designators
2. Read Resistor Color Bands and Printed Codes
3. Use Potentiometers and Identify the Wiper
4. Capacitors: Read Values, Polarity, and Voltage Ratings
5. See How a Capacitor Charges and Discharges
6. Diodes: Identify the Anode, Cathode, and Current Direction
7. LEDs: Check Polarity and Choose a Current-Limiting Resistor
8. Identify Switch Contacts, Connectors, and Fuses

Unit 5: Switch Loads and Choose Safe Power

1. Read a Datasheet Before You Connect a Part
2. Use an NPN Transistor as a Low-Side Switch
3. Use a Logic-Level MOSFET as a Low-Side Switch
4. Relays: Separate the Coil from the Contacts
5. Protect a DC Coil Driver with a Flyback Diode
6. Choose a Power Source and Set a Bench Supply's Current Limit
7. Use Batteries Safely and Match Rechargeable Packs to Their Chargers

Unit 6: Build, Solder, and Inspect Your Work

1. Map Breadboard Connections and Split Power Rails
2. Turn a Schematic into a Breadboard Layout
3. Build and Measure a Switched LED Circuit
4. Build and Check a Transistor-Driven DC Relay Circuit
5. Prepare Wire, Leads, and Through-Hole Parts
6. Control Soldering Heat, Flux Fumes, and Lead Exposure
7. Make and Inspect a Through-Hole Solder Joint
8. Desolder a Part Without Lifting Pads or Damaging Traces

Unit 7: Find Faults One Step at a Time

1. Define the Symptom and Record What Changed
2. Inspect the Circuit with Power Disconnected
3. Check the Source, Polarity, Fuse, and Return Path
4. Compare Expected and Measured Voltages at Test Points
5. Isolate a Suspect Section Before Replacing Parts
6. Work Through a Relay Circuit That Will Not Switch
7. Verify the Repair, Record the Result, and Know When to Stop

Glossary: Essential Bench Terms, Symbols, and Abbreviations