Investigation of Factors Affecting the Capacitance

The capacitor is a common component used in electric circuits. Arduino is a microcontroller that acts as a platform for electronics project.

In our research project, we will write computer programs to turn the Arduino into a capacitance meter so that we could experimentally investigates possible factors that affect the capacitance of a parallel plate capacitor. These factors include temperature, plate area, plate distance, and dielectric materials. We will also determine the mathematical relationship between these factors and the capacitance. Determining the precise relationship between capacitance and variables influencing capacitance would allow us to better control the electric circuit and increase the efficiency of capacitors.

Investigation:

Although there are capacitance meters available on the market, we designed our own way of using the Arduino as a capacitance meter, and have successfully implemented this design. Appendix A contains the procedures we used to turn the Arduino into a capacitance meter; Appendix B contains the Arduino code.

We have also devised the procedures to do Part II of this experiment – determining the relationship between possible factors that can affect the capacitance and the capacitance itself. The parallel plates can be two big pieces of aluminum foil, whose plate area, plate distance can be easily varied. The temperature will be at 4°C, 25°C, and 40°C. The dielectric material between the plates will be air, wood, and… However, we have yet to actualize this plan and will likely perform this part of our project in Spring Break.

science_diagram1

Let t1 and t2 be two different times where V(t1)=0.8V0 and V(t2)=0.2V0. Then we can substitute the above to Equation 1 and obtain: C=ln4xRx(t2-t1), as ln4 and R are constants, this equation can be simplified as:
C=K ΔT  where K is constant, ΔT is the time difference of V(t) reaches 80% and 20% V0.

 Use Arduino to detect the ΔT

science_diagram2

Arduino Code:
Download Sample Code.

Posted in arduino, Science Project

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