Charging capacitor Flashcards Preview

AQA A level (Practical Physics) > Charging capacitor > Flashcards

Flashcards in Charging capacitor Deck (6)
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1

Equipment 

○ Electrolytic capacitor

○ Resistor

○ Battery

○ Voltmeter

○ Switch

2

Method

○ Set up the apparatus as shown in the diagram.

○ Close the switch and observe and record the voltage reading V at time t=0 and at 5s intervals as the capacitor charges until about 120s have passed.

○ Repeat the experiment twice more and obtain the average V for each t.

○ (Like the discharging experiment, this experiment can also be repeated with different resistors or capacitors).

3

Graphs and calculations

○ Plot a graph of V against t. This graph will show an exponential growth curve.

○ V = V0 (1-e^(-t/RC) )

4

Safety 

○ Ensure the capacitor is connected with the correct polarity and that its voltage rating exceeds the voltage of the battery used to prevent it from exploding and releasing harmful chemicals.

5

Improvements and notes

○ The time constant can be found from the exponential growth curve by finding t when the voltage is approximately 63% of the maximum voltage (the voltage of the battery).

6

Diagram