8867 / 2027

Chapter 9

Circuits

Identify the nodes, the measured component and the source model before choosing a circuit equation.

Use physical connections and stated operating conditions to explain measurements and predict useful circuit outputs.

Circuit symbols, resistance and resistivity, I-V characteristics, material temperature effects, internal resistance, resistor networks and potential dividers. For 8867 (2027).

Start readingRevision summaryRead whole chapter

Choose a topic

  1. Read connections and place meters

    Recognise component symbols, preserve node pairs in a redrawing and choose the correct measurement endpoints.

  2. Resistance, material and geometry

    Use matched voltage/current readings, wire dimensions and a reciprocal area graph to distinguish resistance from resistivity.

  3. I-V curves and temperature

    Read four component characteristics and explain typical metal and NTC behaviour using drift and carrier density.

  4. Sources with internal resistance

    Distinguish e.m.f., terminal p.d. and internal loss, and interpret voltage and output-power graphs.

  5. Reduce a network and work back

    Derive series and parallel rules, recover branch values and explain how opening one branch changes the complete circuit.

  6. Potential dividers and sensors

    Select the correct output arm, use potentiometer and sensor responses, and account for a parallel output load.