Name: ____________________________________
Required Practical Title: 9b - Charging a Capacitor
Aim
A clear brief statement of the purpose of this experiment.
To investigate the charging of a capacitor through a resistor and present three electronic charging
curves (V against t) for a 1000 µF capacitor using three different resistors.
Hypothesis
A clear statement of what will happen in the experiment (relate the independent variable to the dependent variable)
with a detailed explanation of why this will happen.
For charging at constant V0, the voltage across the capacitor rises according to V(t) = V0·(1 −
e^(−t/RC)). Therefore, a larger resistor (larger RC) should charge more slowly, so V(t) approaches
V0 more gradually.
Method
A detailed plan of how the investigation will be carried out.
Variables (Independent, dependent and control)
Independent: time t (s) from the start of charging; between runs, resistor value R.
Dependent: capacitor voltage V (V).
Controls: same 1000 µF capacitor, same initial supply V0 (≈6.02 V), same meter and range, same
wiring/switching method, room temperature.
Resolutions used: digital voltmeter 0–10 V (±0.01 V), stopwatch (±0.01 s), resistors ±1–5%
tolerance.
Equipment (List equipment used in the investigation. You could also draw a diagram of how the equipment is set up
– use a pencil and ruler)
Low-voltage DC supply, electrolytic capacitor 1000 µF, fixed resistors 12 kΩ / 47 kΩ / 100 kΩ,
two-way switch, digital voltmeter (±0.01 V), stopwatch (±0.01 s), leads and crocodile clips.
Procedure (A numbered list describing the steps required to carry out the investigation. Refer to all pieces of
equipment and how they are used)
