Litmux Studio

Basic · free course

Electronics Foundations

Voltage, current, resistance and power - and the circuits every product is built from

47 lessons · 12 labs · about 12 hours

Start the courseDo the labs in Litmux Studio

What you will learn

  • Explain charge, current, voltage, resistance, power and energy - with their units - and how they relate
  • Use Ohm's law, the power formulas and Kirchhoff's laws to solve series, parallel and combined circuits
  • Design voltage dividers for sensors, battery monitors and 5 V to 3.3 V signals, allowing for the load
  • Measure voltage, current, resistance and continuity correctly with a multimeter - and avoid blowing its fuse
  • Read resistor colour and SMD codes, pick E-series values, tolerances and power ratings
  • Size batteries in mAh and Wh, understand internal resistance, and use a current-limited bench supply
  • Protect circuits with fuses and work safely with batteries and the mains

Before you start

  • No electronics knowledge is needed
  • Basic arithmetic: multiplying, dividing, fractions and percentages (a calculator helps)
  • Litmux Studio: the labs run in its Electronics Studio

Start here if you are new to electronics. You will learn what electricity really is, how voltage, current, resistance, power and energy fit together, and how to work out any circuit of resistors with Ohm's law and Kirchhoff's laws. A whole section goes deep into the voltage divider - the circuit behind battery monitors, light and temperature sensors, volume knobs and 5 V to 3.3 V signals - including the loading effect that catches out so many beginners. You will learn to use a multimeter properly, read resistor codes and choose standard values and power ratings, understand batteries, bench supplies and fuses, and work safely. Every idea is measured in the live simulator, and the course ends with two design projects: a solar battery monitor on an Arduino Nano and an incubator thermometer bridge.

The lessons

1. What electricity is

  1. LessonCharge, electrons and conductors12 min
  2. LessonCurrent and voltage15 min
  3. LessonResistance, open circuits and short circuits15 min
  4. LabLab: your first circuit15 min
  5. QuizQuiz: what electricity is6 min

2. Ohm's law

  1. LessonOhm's law: V = I × R15 min
  2. LessonOhm's law at work: LEDs, cables and current shunts16 min
  3. LabLab: Ohm's law on the bench15 min
  4. QuizQuiz: Ohm's law6 min

3. Power and energy

  1. LessonPower: how fast energy is used15 min
  2. LessonHeat in resistors and power ratings13 min
  3. LessonEnergy: watt-hours, kWh and battery capacity16 min
  4. LessonPractice set: Ohm's law, power and energy20 min
  5. LabLab: power and the resistor's rating15 min
  6. QuizQuiz: power and energy7 min

4. Series and parallel circuits

  1. LessonSeries circuits14 min
  2. LessonParallel circuits15 min
  3. LessonKirchhoff's laws: current at a junction, voltage round a loop15 min
  4. LessonSolving combinations and the current divider15 min
  5. LabLab: series, parallel and Kirchhoff18 min
  6. QuizQuiz: series and parallel circuits8 min

5. The voltage divider

  1. LessonThe voltage divider: how and why it works16 min
  2. LessonSensors and knobs: dividers that change17 min
  3. LessonBattery monitors, level shifting and bias17 min
  4. LessonThe loading effect - and why a divider is not a power supply17 min
  5. LessonPractice set: voltage dividers20 min
  6. LabLab: a divider under load15 min
  7. LabLab: light and temperature sensors15 min
  8. QuizQuiz: the voltage divider8 min

6. Using a multimeter

  1. LessonMeet the multimeter14 min
  2. LessonMeasuring voltage and current - and the classic mistakes15 min
  3. LessonMeasuring resistance and continuity13 min
  4. LabLab: multimeter skills20 min
  5. QuizQuiz: using a multimeter7 min

7. Real resistors: values, codes and tolerance

  1. LessonReading resistor values: the colour code and SMD codes15 min
  2. LessonStandard values, tolerance and resistor types16 min
  3. LabLab: combining resistors with the ohmmeter15 min
  4. QuizQuiz: real resistors6 min

8. Power sources and safety

  1. LessonCells and batteries: voltage, capacity and packs16 min
  2. LessonInternal resistance: why the voltage sags under load15 min
  3. LessonBench supplies, adapters and the current limit14 min
  4. LessonElectrical safety: shock, fire and batteries15 min
  5. LabLab: internal resistance and the current limit18 min
  6. LabLab: a fuse saves the wiring12 min
  7. QuizQuiz: power sources and safety8 min

9. Projects

  1. ProjectProject: a solar battery monitor30 min
  2. ProjectProject: design and verify an incubator thermometer30 min

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