Day17

Capacitors in Series and Parallel

1. A Capacitance Puzzle:
Predict: When the Capacitor connected in parallel. The capacitance equals to the sum of the each capacitance.
Experiment set up:

2. Quantitative measurements on an RC system.

Predict: When the battery is removed or turn off from the circuit, the voltage across the capacitor will stay same, because the charged battery will lose the potential energy across the resistor, but the circuit is an open circuit, the potential energy does not lose. Since, it is stay st same.
Experiment set up:

In the experiment, our predict is acceptable. But during the measuring, we found it is not perfect march because some of  potential energy from the capacitor is restored by wire.

Activities: Calculation of unknown capacitor:

 With the equation Ae^(-ct) + B，a best fit line is made for each of the graphs. The relationship between potential/voltage and time for a charged capacitor can be conclused VC=Vmax (1-e*(-t/RC)) and for a discharged capacitor it is VD=Vmaxe^(-t/RC). In our lab, the initial voltage is not correct because we do not start from 0. So when LoggerPro tries to do best fit line, it does not start at the right time.