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Electronics Basics

Easy to follow, lower secondary (about age 13–15).

Tip: The videos also have an English audio track. On YouTube, open ⚙ Settings → Audio track.

17:00

Episode 1

Series & Parallel Circuits Explained

What you will learn

  • recognise whether components are connected in series or in parallel
  • the rules for current, voltage and resistance in both circuits
  • calculate total resistance, partial currents and partial voltages
  • advantages, disadvantages and where each circuit is used
  • the typical mistakes that cost points in exams
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12:39

Episode 2

Mixed Circuits Explained

What you will learn

  • recognise sub-circuits by following the path of the current
  • the four-step method: circle, combine, total current, work backwards
  • two complete worked examples with voltages and currents
  • Kirchhoff's current and voltage laws as a quick check
  • speaker cables, house wiring, fairy lights and car tail lights
  • the four most common mistakes
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12:33

Episode 3

Voltage Divider & Power Explained

What you will learn

  • voltage divider: how the voltage splits in the ratio of the resistors
  • potentiometer and light-dependent resistor (LDR)
  • power P = U · I and reading rating plates
  • energy in kWh and electricity costs in Swiss francs
  • which resistor gets hot – in series and in parallel
  • short circuit, fuse, residual-current device (RCD) and why you never daisy-chain power strips
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11:52

Episode 4

The Capacitor Explained

What you will learn

  • structure: two plates with an insulator in between – and the circuit symbol
  • charging: why the current starts large and keeps getting smaller
  • capacitance in farads and microfarads, and the maximum voltage printed on the case
  • discharging through an LED: bright at first, then dimmer and dimmer
  • time constant τ = R · C: about 63 % after 1 τ, practically full after 5 τ – with two worked examples
  • capacitor or battery? Camera flash, touchscreen, power supply and supercapacitors
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11:58

Episode 5

Induction & AC Explained

What you will learn

  • current creates a magnetic field: electromagnet, crane, loudspeaker, relay
  • induction: only a changing magnetic field creates a voltage
  • dynamo and generator – and where Swiss electricity comes from
  • alternating current at 50 hertz, RMS value 230 V and peak 325 V
  • transformer: voltages in the ratio of the turns – with a worked example
  • why high voltage, induction hobs and wireless charging
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11:34

Episode 6

Semiconductors & Diodes Explained

What you will learn

  • conductor, insulator, semiconductor – and why silicon matters so much
  • doping: free electrons (n) and holes (p)
  • the pn junction: depletion layer, forward from about 0.7 V, reverse direction
  • circuit symbol, anode and cathode – fitting diodes and LEDs the right way round
  • calculate the LED series resistor and round to the E12 series – with two worked examples
  • reverse-polarity protection, solar cell, power supply and the infrared LED in the remote control
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10:58

Episode 7

Rectifiers Explained

What you will learn

  • why electronics needs direct current – and what the wave and line on the charger mean
  • half-wave rectifier: one diode, only one half-wave
  • bridge rectifier: four diodes, both half-waves, 1.4 V loss
  • smoothing with the reservoir capacitor and what the ripple voltage is
  • from plug-in transformer to DC – with a worked example and the right capacitor voltage
  • switched-mode power supply, bicycle dynamo with USB and the car alternator
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10:15

Episode 8

Special Diodes Explained

What you will learn

  • the Zener diode: controlled breakdown and a fixed voltage
  • stabilising a voltage: calculating the series resistor (12 V → 5.1 V)
  • why the Zener diode always needs a series resistor
  • flyback diode: protection against the voltage spike of relays and motors
  • photodiode and solar cell: light becomes current (0.5 V per cell)
  • laser diode, Schottky diode, varactor diode
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10:06

Episode 9

The Transistor as a Switch Explained

What you will learn

  • base, collector, emitter: how a transistor switches
  • the NPN circuit symbol and the pins of the BC547
  • current gain: small base current, large collector current
  • calculating the base resistor (5 V pin, LED with 20 mA)
  • switching a relay – with a flyback diode
  • LED strip on a microcontroller: separate power supply, common ground
  • the core of the twilight switch: light sensor at the base
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10:09

Episode 10

Build a Twilight Switch

What you will learn

  • reading the circuit diagram in stages: sensor, switch, smoothing, relay
  • the parts list: potentiometer, light sensor, BC547C, LED, electrolytic capacitor
  • building it on the breadboard, step by step
  • measuring with the multimeter: midpoint, base, collector
  • a relay with flyback diode switches an LED strip
  • troubleshooting: the four most common building mistakes
  • looking back at the whole series
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