Capacitor Charging/Discharging

Purpose: To observe the properties of a capacitors in their charging and discharging states.

Introduction: 
We have 2 different circuit models for the charging and discharging with Thevenin equivalent as shown:

We want to design build and test a circuit that does the following:

• utilizes a 9V power
• Employs a charging interval of 20s with a stored energy of 2.5mJ
• discharges the 2.5mJ in 2s

   To fulfill these requirements we have the following for charging resistance and capacitance:

       The peak discharge current and discharge and resistance were then calculated.

 Experiment:
     The actual charge and discharge resistances used are as follows along with the voltage source.

      The circuit was then built. For capacitance we used 3 capacitors is parallel and hooked up logger pro voltage sensors.

     The   Charging and discharging was recorded on logger pro.

     Data:

The charging curve:

     The capacitor charges up to about 8.5V. The reasons for it not charging all the way are a leak resistance which is inherent to every capacitor. The main reason for the biggest loss is that logger pro capped it off around this voltage.

The discharging curve:

     The capacitor doesn't completely discharge in 2 seconds but it is extreemely close.

Conclusion:

     The charging and discharging of capacitors is exponential and the time to make them discharge and charge can be easily controlled by changing the value of the resistance and/or capacitors.

Practical Question: