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CODESAFE CANADA · STUDY RESOURCES

Work it through. Check it. Revisit it.

A revision sheet for G3, G2, electrical and other trade learners.

01 · A formula is a relationship

For a simple resistive DC circuit: V = I × R · I = V ÷ R · R = V ÷ I

Voltage V in volts (V); current I in amperes (A); resistance R in ohms (Ω).

Worked example: 24 V ÷ 48 Ω = 0.5 A = 500 mA. At the same voltage, twice the resistance gives half the current.

02 · Keep the units on every line

ConvertOperationExample
in → mm× 25.42.5 in = 63.5 mm
ft → m× 0.304810 ft = 3.048 m
kW → W× 1,0001.5 kW = 1,500 W
mA → A÷ 1,000500 mA = 0.5 A
°F reading → °C(°F − 32) × 5/968 °F = 20 °C

For a temperature difference, use the scale factor only. Nominal pipe sizes are labels, not dimensions for direct conversion.

03 · Record a codebook lookup you can repeat

  • Identify the topic, equipment, conditions, units, and requested result.
  • Locate the topic using your assigned reference’s contents or index; check the scope.
  • For tables, read the row, column, units, and applicable notes together.
  • Record the title, edition, clause/table, conditions, and your explanation.

Reference + edition: ____________________________________________________

Clause/table + conditions: _________________________________________________

04 · Turn one mistake into a study task

Question/topic:
My mistake and its cause (concept, formula, units, wording, or time):
The correction in my own words:
One new example to solve + when I will revisit it:

Original CodeSafe study worksheet · September 12, 2026 · codesafeca.com/resources
Worked lessons and reference links: codesafeca.com/resources/ohms-law and codesafeca.com/resources/unit-conversions.
Use your program’s assigned references and exam provider’s rules. This sheet is a study aid, not a gas installation reference.