How electronic components work
What each part is, what happens inside it, how to recognise it and how it is used. Pick a part to read about it.
Passives
- Resistor : Limits how much current flows; turns the excess into heat.
- Potentiometer : An adjustable resistor — a knob or slider.
- Capacitor : Stores a little charge, like a tiny rechargeable tank.
- Inductor : A coil of wire that resists changes in current.
- Transformer : Two coils on one core that change AC voltage up or down.
- Crystal : A sliver of quartz that vibrates at one very precise frequency.
Diodes
- Diode : A one-way valve for current.
- LED : A diode that gives off light when current flows through it.
- Zener & TVS diode : A diode built to conduct backwards at a set voltage.
Transistors
- MOSFET : An electronic switch controlled by voltage.
- Transistor (BJT) : A transistor where a small base current controls a bigger collector current.
Chips
- Op-amp & comparator : An amplifier chip that makes a small voltage bigger.
- 555 timer : A classic chip that makes timed pulses and blinking signals.
- Logic gates : A tiny circuit that makes a yes/no decision from yes/no inputs.
Power & protection
- Battery : A store of chemical energy that gives a steady voltage.
- Voltage regulator : Turns a higher, messy voltage into a steady lower one.
- Fuse & PTC fuse : A deliberate weak link that melts to stop too much current.
Switches & motion
- Switch & push button : Opens or closes the loop. Click it in the schematic!
- Relay : A switch flipped by an electromagnet.
- Buzzer & speaker : Turns an electrical signal into sound.
- DC motor : Turns current into spinning motion using magnets and coils.
Sensors & isolation
- Thermistor : A resistor whose resistance changes with temperature.
- Light sensors (LDR & photodiode) : A resistor whose resistance falls as light gets brighter.
- Optocoupler : An LED and a light sensor sealed together, to pass a signal across a gap.
Circuit building blocks
- Amplifier classes : How long the output transistors are on during each wave: A, B, AB, C or D.
- Transistor biasing : The steady DC that sets where a transistor rests before any signal arrives.
- Multivibrators : A circuit that flips between two states: astable, monostable or bistable.
- Oscillators : A circuit that makes its own steady wave from DC.