# An experiment on the variables and constants of the capacitor

One terminal of each capacitor should be marked with a definite polarity sign. ## Introduction

The friendliest, high quality science and math community on the planet! Everyone who loves science is here! The procedure entailed using a wave generator and an oscilloscope to graph the charging and discharging patterns of the capacitor.

We did four trials using different capacitors and resistances, but I will only use one as an example to get the idea of what we did across. The wave generator was set to produce square waves and cause the capacitor to charge and discharge constantly. The oscilloscope terminals were attached to the circuit on each side of the capacitor and after some fine adjusts on the range of voltage and time, a nice charging pattern was produced.

In this case, the max voltage reached is 10 volts. After filming the charging pattern, we plotted some easy to determine points for t, V to replicate the curve in Excel. We were told by our instructor that Vo would be the max values for voltage that your data is heading to, and since a good portion of our graph our data values are nearly at 10V, we take Vo to be 10V.

Our objective is to compare the time constant that our experiment data is indicating to the theoretical time constant we get from measure R and C directly.

## Time Constant ≠ Time constant from experiment | Physics Forums

The resistance R and capacitance C was measured using an multimeter, where R was measured on the ohmmeter setting and the capacitance was measured by first discharging it and then inserting it into slits in the multimeter for this specific use and using the capacitance setting.

To determine the time constant indicated by our data, we then changed the capacitance C to change the time constant until the curve mapped to the data points.

Relevant equations Voltage over a capacitor is: However, according to the theoretical curve the time constant must be close to 4. To figure out what might be causing this discrepancy I have looked at if any possible error involved in measuring R or C could make the graph be off so much.

To get the theoretical curve to map to the data points I either have to decrease C by 5. Both of these seem seem like impossible errors especially considering that the multimeter should have been able to read accurately I have been reading that measuring capacitance is not the easiest thing to do, but our meter seemed to read it just fine.

## Discussion of Principles

However, maybe this is not a very accurate method? For the three other trials we did another single capacitor, two capacitors in series, and two capacitors in parallelwe have the same issue. In all four, the theoretical curve is always lower than the curve indicated by the data points, which I assume is the effect of some issue that happened in all four trials. Any help is greatly appreciated.Experiment 5: RC Circuits Abstract The purpose of this lab is to learn and understand RC Circuits. An RC circuit is composed of at least one resistor and at least one capacitor. 1 47µF capacitor 1 Kelvin DMM leads The object of this experiment is to measure the time constant for a number of RC circuits.

Theory: When a charged capacitor discharges through a resistance, the potential difference across the capacitor decreases exponentially. to “variables (column). Student experiment: Varying R and C The previous experiment produced graphs of the discharge for a particular combination of resistor and capacitor. This can be extended by looking at the decay for a range of values of C and R. Introduction to the constants for nonexperts.

a fundamental constant experiment of current interest is also described: the determination of the fine-structure constant by means of the quantum Hall effect and calculable cross capacitor. E and m are variables and c is invariant, a constant of the equation.

## Ian Hickson's Capacitor Experiment

In quantum theory, the. difference (from the previous parts) across the capacitor, calculate the theoretical value of the time constant for the black (C=µF) capacitor and then determine the experimental value of .

Constants. In all equations quoted in this report, V is the voltage across the capacitor, t is the time elapsed since the start of the discharge, V 0 is the value of V at t=0, and C is the capacitance of the capacitor being discharged.

Capacitor Charging and Discharging | DC Circuits | Electronics Textbook