Calculating the Electrical Charge of Capacitors

Objective: Using mathematical equations, demonstrate how to calculate the charge across a capacitor, or a device that can store energy in the form of electricity.

Instructions: 1. Turn off all electronic devices, and be aware of any electric fields that might be present. 2. Solve the following equations to determine the charge of a capacitor, where C is the capacitance, t is the change in time, and V is the voltage. Q = V x C Q = (V_init - V_final) x C

1. Here are some specific examples: a. Consider a capacitor with a capacitance of 6 microfarads at a constant voltage of 3 volts. Calculate the charge on the capacitor: Answer: Q = 3 V x 6 µF = 18 µC

b. At time 0, a capacitor with a capacitance of 8 nanofarads is at 5 volts. Five seconds later, the voltage across the capacitor has dropped to 3 volts. Calculate the charge on the capacitor: Answer: Q = (5 V - 3V) x 8 nF = 16 nC

1. Check your answers with a calculator to ensure accuracy.

2. Discuss any observations or questions with your instructor.