4/13 Capacitor Voltage-current Relations & Inductor Voltage-current Relations

We talked about capacitors and Inductors today.

Capacitor

A capacitor consists of two conducting plates separated by an insulator (or dielectric). (From Day 15 Capacitors and Inductorsb.pdf)

The unit is farads (F).

We started with figuring out the unit of the capacitance. 

C is proportional to area/distance which is the unit m.

In order to get the correct unit, we need to have a constant which is the permittivity of the dielectric material between the plates.

Next, we did a example.

The video is when we apply too much voltage to the capacitor. We exploded a capacitor.

Capacitor Voltage-current Relations

Pre-lab

We predicted that the capacitor voltage and the capacitor current if the capacitor voltage is a sinusoidal wave and a triangular wave.

The picture below is the prediction.

The picture below is the basic set up for this lab.

The actual resistance is 99.2 ohms.

The picture below is when applying a sinusoidal input voltage with frequency = 1kHz, amplitude = 2V, and offset = 0V to the circuit.

The picture below is when applying a sinusoidal input voltage with frequency = 2 kHz, amplitude = 2V, and offset = 0V to the circuit .

The picture below is when applying a triangular input voltage with frequency = 100 Hz, amplitude = 4V, and offset = 0V to the circuit.

Next, we leaned how to deal with the problem that the capacitors are series or parallel. It's the opposite of resistors.

For the example above, the equivalent capacitance would be 20 micro farads.

Inductor

An inductor consists of a coil of conducting wire. (From Day 15 Capacitors and Inductorsb.pdf)

The unit is henrys (H).

We did a example. 

By applying the equation, we got the energy stored in the inductor at t = 1s would be 35.7J.

Then, we did the second lab.

Inductor Voltage-current Relations

The actual resistance is 99.2 ohms.

The picture below is the basic set up for this lab.

The picture below is when applying a sinusoidal input voltage with frequency = 1kHz, amplitude = 2V, and offset = 0V to the circuit.

The picture below is when applying a sinusoidal input voltage with frequency = 2 kHz, amplitude = 2V, and offset = 0V to the circuit.

Summary

We leaned how capacitors and inductors work in the circuits, and how to calculate the equivalent capacitance when the capacitors are in series or parallel, and why we use capacitors and inductors in a circuit. Also, we learned the important equations for calculating the energy stored in the capacitors and the energy stored in the inductors.