Arduino›Level 4 · Cert Prep›Lesson 46

Level 4 · Lesson 46 · Exam · ARD-L04-46

Domains 1–4 Walkthrough

90 minutes · Ages 13–16 · Cluster I · Certification Exam Preparation

Learning Goals 5 min

Today we drill domains 1-4: electricity, schematics, components, IDE+boards. Sample questions with full explanations. By the end you will:

  1. Solve the typical "calculate the resistor" / Ohm's-law questions.
  2. Identify common schematic symbols at speed.
  3. Match components (capacitor, transistor, IC) to their roles.
  4. Pick the right board / IDE setting for a scenario.

Warm-Up 5 min

Pen + paper. Time yourself. Aim for < 2 minutes per question.

Sample Questions · Domains 1-4 60 min

Domain 1 · Electricity

Q1

A circuit has 9 V and 470 Ω. Current through the resistor?

Answer

I = V/R = 9 / 470 ≈ 19.1 mA. Rounded to common option: ~19 mA.

Q2

Two 220 Ω resistors in parallel. Equivalent resistance?

Answer

1/Req = 1/220 + 1/220 = 2/220. Req = 110 Ω.

Q3

A 5 V battery drives a 100 Ω resistor. Power dissipated?

Answer

P = V²/R = 25 / 100 = 0.25 W. A 1/8 W resistor would burn; need ≥ 1/4 W.

Q4

What does AC mean?

Answer

Alternating Current — current reverses direction periodically (e.g. household mains 50/60 Hz).

Domain 2 · Schematics & Datasheets

Q5

The symbol with two parallel lines, one shorter, represents:

  1. Resistor
  2. Capacitor
  3. Diode
  4. Battery
Answer

Battery (4). Long line = +, short line = −. Capacitor symbol has two equal-length lines (or curved one for polarised).

Q6

A diode symbol shows current flowing in which direction (when forward-biased)?

Answer

Anode (triangle) to Cathode (line). The triangle points in the direction current flows.

Q7

An NPN transistor's three pins are:

Answer

Base (control), Collector (top, current enters), Emitter (bottom, current exits). On the symbol the arrow points OUT of the emitter for NPN.

Q8

In a datasheet, "Absolute Maximum Ratings" means:

Answer

The values beyond which the chip will be damaged. Do NOT exceed. Different from "recommended operating conditions".

Domain 3 · Components

Q9

You want to read a button. Which is correct?

  1. Button between pin and GND, pinMode(pin, INPUT); pressed = HIGH.
  2. Button between pin and GND, pinMode(pin, INPUT_PULLUP); pressed = LOW.
  3. Button between pin and 5V, pinMode(pin, INPUT_PULLUP); pressed = HIGH.
  4. Button between pin and 5V, pinMode(pin, INPUT); pressed = LOW.
Answer

2. INPUT_PULLUP holds the pin HIGH internally; the button pulls it LOW when pressed.

Q10

What does a flyback diode protect against?

Answer

The inductive voltage spike when a motor / relay / solenoid is switched off. Diode reverse-biased across the inductor catches the spike.

Q11

An LDR (light-dependent resistor):

  1. Generates current when light hits it.
  2. Decreases resistance in bright light.
  3. Increases resistance in bright light.
  4. Is unaffected by light.
Answer

2. Resistance drops with light intensity. Use in a voltage divider; analogRead gives brightness.

Q12

The function of a 100 nF capacitor next to a chip's VCC:

Answer

Decoupling — smooths supply noise at the chip's power pins, preventing brown-outs during sudden current spikes.

Domain 4 · IDE & Boards

Q13

The Arduino IDE's Boards Manager is for:

Answer

Installing support for additional board families (ESP8266, ESP32, Nano 33 BLE). Adds them to the Tools → Board menu.

Q14

A sketch shows "Region `data' overflowed". What does it mean?

Reveal

The static RAM usage exceeded the chip's capacity. Fix: move strings to flash with F(), reduce arrays, or upgrade to a board with more RAM.

Q15

The bootloader on an Arduino UNO is roughly:

  1. 2 KB of flash
  2. 0.5 KB of flash
  3. 32 KB of flash
  4. 1 KB of RAM
Answer

2. ~0.5 KB. Of the 32 KB total flash, ~31.5 KB is usable for sketches.

Q16

To upload via "Arduino as ISP", you connect:

Answer

Programmer's D10 → target RESET, D11 → MOSI, D12 → MISO, D13 → SCK, plus power + GND. ArduinoISP sketch on the programmer; Tools → Programmer = Arduino as ISP; Tools → Burn Bootloader.

Try It Yourself · Time test 15 min

Take all 16 questions. Time yourself. Aim for < 30 minutes. Tally your score.

  • 14-16 right: solid on domains 1-4.
  • 10-13: revisit specific weak topics.
  • < 10: spend the next 2 days re-reading L01, L02, and the L04-01..06 lessons.

Mini-Challenge · Write your own 10 min

Write 3 of your own multiple-choice questions for these domains. Swap with a classmate; mark each other. Writing tests is the best way to identify the boundaries of your knowledge.

Recap 5 min

Domains 1-4 = electricity, schematics, components, IDE. Quick mental maths (Ohm's law). Recognise symbols. Match components to roles. Tomorrow: domains 5-8.

Voltage divider
Two resistors splitting a voltage. Common for sensors that vary in resistance (LDR, thermistor, pot).
Series / parallel
R_series = R1 + R2. R_parallel = (R1 × R2) / (R1 + R2). Or for N equal: R_parallel = R / N.
Forward bias
The polarity where a diode conducts. Anode + to cathode −.
Datasheet sections
Absolute max, recommended operating, electrical characteristics, pinout, application notes. Read in that order.
INPUT_PULLUP
Pin mode that enables the AVR's internal pull-up resistor. Saves an external resistor for buttons.
Bootloader
Small program in flash that allows USB-based sketch upload. ~0.5 KB on UNO.

Homework 5 min

  1. Score the 16 questions. Note weak spots.
  2. Re-read the relevant L01/L02 lessons for each miss.
  3. Read ahead to ARD-L04-47 (Domains 5-8).