Lesson 16

Card 2.1: Ohm's Law

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Format: Bench measurement

Time: 40 min

Prerequisites: None

Core Question

Voltage, current, resistance: three numbers locked together by V = IR. If you can measure any two, you know the third. Can you prove the law is real at the bench?

Resource (~10 min)

Multimeter basics demo: measuring voltage (across), current (through, meter in series), and resistance (component isolated). The three most common meter mistakes, shown live: wrong port, wrong mode, measuring resistance in a live circuit.

Activity

Build the simplest circuit: battery pack, resistor, jumpers. For three different resistors: measure R directly, measure V across it, measure I through it, and check whether V = IR holds within reason. Record all nine numbers in a table.
One prediction round: given the battery voltage and a fourth resistor’s band code, predict the current BEFORE wiring it. Then wire and measure. Circle your error percentage.

Clearing This Card

The data table with the prediction round, plus a 90-second oral check: “A thruster draws 10 A at 12 V. What is its effective resistance, and what happens to current if a corroded connector adds 1 ohm in series?”

If You Miss This Class

Bench kit stays in the bin for two weeks; same activity and check during studio time.

Why This Matters

Every fuse choice, tether calculation, and burned component conversation this season stands on this card. It is the prerequisite for 2.2 and 2.5.