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Section Summary: Electronics Primer
Activities 2.1 – 2.3. Use this to review, or to fill in a definition you missed.
1. Voltage, Current, and Resistance
Three quantities describe what is happening in any circuit: how hard the charge is being pushed, how much of it is moving, and how much the circuit fights that movement.
- Voltage
- The electrical "push" that makes charge move, measured in volts (V).
- Current
- The rate charge flows past a point, measured in amps (A).
- Resistance
- Opposition to the flow of charge, measured in ohms (Ω).
- Conventional Current
- The historical convention that current flows from + to − in a circuit diagram, opposite the actual direction electrons move.
2. Reading a Circuit
A schematic tells you what to build without telling you where to put it. Your job is to translate those symbols onto a breadboard, whose rows are already wired together underneath.
- Schematic
- A diagram describing a circuit using standardized symbols.
- Breadboard
- A reusable prototyping board whose short rows (and long outer rails) connect groups of holes electrically.
- Resistor
- A component that limits current flow, often to protect other components.
- Anode / Cathode
- The positive (anode, longer leg) and negative (cathode, shorter leg) sides of an LED.
- Ground (GND)
- The circuit's reference point, where current returns to complete the loop.
3. Ohm's Law and the Microcontroller
Ohm's Law tells you what resistor a circuit needs. A microcontroller then lets code decide what those circuits do, one pin at a time.
- Ohm's Law
- The relationship V = I × R between voltage, current, and resistance.
- Microcontroller
- A tiny computer that controls a circuit's voltage and current by following code.
- GPIO
- General Purpose Input/Output — a microcontroller pin that code can control.
- Digital Pin
- A pin with exactly two states: HIGH (on) or LOW (off).
- Object
- Something that bundles data and actions together — like a Pin, which knows its number and direction, and has actions you can call on it.
- Method
- An action you call on an object using dot notation, like
led.value(1).