Explore the connections.

• 4.3.1(a) Apply Kirchhoff’s second law as conservation of energy in electrical circuits.
• 4.3.1(b) Apply Kirchhoff’s first and second laws to analyse electrical circuits.
• 4.3.1(c) Calculate total resistance of resistors in series using R = R₁ + R₂ + …
• 4.3.1(d) Calculate total resistance of resistors in parallel using 1/R = 1/R₁ + 1/R₂ + …
• 4.3.1(e) Analyse circuits with components including both series and parallel arrangements.
• 4.3.1(f) Analyse circuits with more than one source of e.m.f.
• 4.3.2(a) Define source of e.m.f. and internal resistance.
• 4.3.2(b) Define terminal potential difference and 'lost volts'.
• 4.3.2(c)(i) Use and apply E = I(R + r) and E = V + Ir for internal resistance.
• 4.3.2(c)(ii) Use techniques and procedures to determine the internal resistance of a cell or power supply.
• 4.3.3(a) Describe potential divider circuits with fixed components and potentiometers.
• 4.3.3(b) Describe potential divider circuits with variable components such as LDRs or thermistors.
• 4.3.3(c)(i) Use potential divider equations Vout = (R₂ / (R₁ + R₂)) × Vin and V₁ / V₂ = R₁ / R₂.
• 4.3.3(c)(ii) Use techniques and procedures to investigate potential divider circuits including sensors.

H156 v2.0 · May 2026