A-Level Physics OCR A H556

(i) charging and discharging capacitor through a resistor

(ii) techniques and procedures to investigate the charge and the discharge of a capacitor using both meters and data-loggers

PAG9

time constant of a capacitor–resistor circuit; $τ = CR$

equations of the form $x = x_0e^{-t/(CR)}$ and $x = x_0\Big(1 - e^{-t/(CR)}\Big)$ for capacitor–resistor circuits

Learners will be expected to know how lnx–t graphs can be used to determine CR.

graphical methods and spreadsheet modelling of the equation $\dfrac{ΔQ}{Δt} = -\dfrac{Q}{CR}$ for a discharging capacitor

exponential decay graph; constant-ratio property of such a graph.