Thursday, April 16, 2015

Day 15 - Tuesday, April 14, 2015 - Capacitor Voltage-current Relations

Today we reviewed capacitors. A capacitor stores energy in an electric field. It is usually thought of as two parallel plates with the same magnitude of charges but different signs.

Also capacitance can change with the dimensions of the plates. \




Our diagram for capacitors does not represent a fundamental reality of capacitors which is that they are polarized. So since now we are recognizing this, we are going to draw it differently.

Capacitors can also change capacitance and we draw them like this.

Also, we can classify capacitors as axial and radial.

They can also be classified as electrolytic and tantalum capacitors. Tantalum capacitors are dry devices unlike the electrolytic capacitors. They are most useful when the circuit needs to be stable when temperature changes. In these capacitors, d is incredibly small.

There are also super capacitors

Capacitors are also rated according to their voltage.

There are also ceramic capacitors which usually have very small values. They are cheap.

There are many types of capacitors. A notorious type are capacitors of silver-mica. Mica is a national occurring type of rock that cuts in plates of rocks.

There are also adjustable capacitors.

There are also pyester film capactiors which uses a thin pyester film as a

Then we worked with equations and derived the energy in a capacitor.



In circuits, capacitors act as a short which means that we can draw them as open circuits.


Then we did our lab called Capacitor Voltage-Current Relations


Below is a picture of our circuit.



For our first input signal we put in a sinusoidal signal of amplitude = 2 V and offset = 0. And we tried three different frequencies:

a. Frequency = 1kHz


b. Frequency = 2kHz


c. Frequency = 100 Hz. Also, we changed the amplitude to 4 V.





For our second input signal, we put in a triangular signal with amplitude of 2 V and offset = 0. And we tried to see three frequencies:

a. Frequency = 1kHz


b. Frequency = 2kHz


c. Frequency = 100 Hz and we changed the voltage to 4 V





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