Unit: Electricity Task 2: Practical to investigate the charging and discharging a capacitor (AC 1.1, 3.1) 1) You are provided with a capacitor C, a resistor R, a battery, a voltmeter, a two way switch, connecting wire and a stop watch. 2) Construct the circuit as shown in the diagram. R - 1 mega ohm positive R capacital stor charge 3) Adjust the switch to fully charge the capacitor. Measure the potential difference across the capacitor, Vo. 4) Adjust the switch to allow the capacitor to discharge through the resistor and start the stop clock. Measure the potential difference across the capacitor every 10s until the capacitor has almost discharged. 5) Plot a graph of potential difference against time (Graph A). 6) Plot a graph of In V against t (Graph B). Measure the gradient of the graph and use it to find the time constant of the circuit (t = - 1/gradient). Compare this to the value of the time constant using the nominal values of C and R (t = CR) Analysis and Discussion a) Use information about the structure of a capacitor to explain why charge builds up and is stored on the plates of the capacitor when the switch is in position 1. b) Use information from the graph A to predict how the current through the resistor changes as the capacitor discharges. c) Explain why the capacitor charges much more quickly than it discharges. d) Design a circuit that would take three times longer to discharge the capacitor. When you have completed your assignment check that you have met the assessment criteria: 1.1 Explain the mechanisms of electrical conduction in terms of movement of charge carriers. 3.1 Analyse the charging / discharging of a capacitor in a DC circuit. Every to see 220 MF 1 MM