Review and Practice

Measure Resistance: Self-check

• In this activity, you:
  • built and used an ohmmeter to measure resistors,
  • learned a resistor measurement rule, and
  • learned how to calculate the resistance across series and parallel circuits.
• Did your ohmmeter function correctly?
• Were you able to accurately measure resistance?
• Do you understand how to properly measure a resistor?
• Can you calculate the resistance across series and parallel configurations?

Questions

1. What property does an ohmmeter measure?
2. Can an ohmmeter measure an individual resistor’s resistance in-circuit?
3. What term is used to describe two resistors that are connected end-to-end?
4. In simple terms, how are two resistors connected if they are in series?
5. When you connect the micro:bit ohmmeter’s alligator clips to the resistor, what circuit does it form for measuring resistance through creating a corresponding voltage?  Hint: if your alligator clip is grabbing resistors at each end, it connects them in series.

Exercises

1. Calculate the equivalent resistance of two 220 Ω and two 1000 Ω resistors, all connected in a single series circuit.
2. Calculate the equivalent resistance of ten 1000 Ω resistors, all connected in a single series circuit
3. Calculate the equivalent resistance of four 1000 Ω resistors, all connected in a single parallel circuit

Projects

1. Calculate the resistance of two 1000 Ω resistors and one 220 Ω resistor, all connected in series.  Draw the circuit schematic and build the circuit.  Measure its resistance to verify that your calculations and circuit building are correct.
2. Calculate the resistance of two 1000 Ω resistors and one 220 Ω resistor, all connected in parallel.  Draw the circuit schematic and build the circuit.  Measure its resistance to verify that your calculations and circuit building are correct.