Research Question:How does the theoretical prediction for the decay curve of an
RC circuit compare to the experimental data?
You will observe and measure what happens to the voltage across a capacitor
when it is placed in series with a resistor in a direct current circuit. For the activities
in this lesson you will need:

CircuitElements
*Battery (~ 4.5 V)
*2 capacitors (0.47mF)
*3 resistors of same value (~MW!)

Measuring Devices
*Digital multimeter

*Capacitance meter

*MBL ScienceWorkshop System

Quantitative Measurements of an RC System

Your task is to make a quantitative study of an "RC" system. You will do this
by connecting the MBL voltage input across the capacitor and view the trace of
voltage vs. time in graphical form as the capacitor discharges.

Circuit Arrangement

Procedure

1.Carefully measure the value of the capacitor, the resistor, and the resistance of
the voltage sensor with the appropriate meters. Record these values in your
Word report file.

2.Hook up the circuit and also measure the effective resistance of the circuit.
Compare this effective resistance with the individual measured values. Does it
make sense? Why or why not?

3.Based on the values of C and R_eff, predict what the RC time constant will be for
this circuit.