Electrical Engineering - Design Problem - Capacitors

In summary, the problem is to design a capacitor with given power output, time, operation voltage, and properties of dialectic and metal materials. The machine making the capacitor has thickness restrictions. Equations are provided for capacitance, charge, energy, voltage, current, and unit conversions. Material 3 was chosen for the dialectic material with the resulting capacitance, charge, and energy calculated. Further guidance is needed for solving the problem.
  • #1
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Problem
Given the power that is needed to be output by the capacitor - P
the length of time that the capictor must give off that power - t
the maximum operation voltage that the capacitor can operate at- V
the dialectric constant of several materials - ε
the breakdown field of those several materials - [itex]U_{d}[/itex]
and the mass density of those several materials - ρ
Design the capacitor that meets these requirements

Dialectic Material 1
ε= [itex]4ε_{0}[/itex]
[itex]U_{d} = 1 \frac{V}{nm}[/itex]
[itex]ρ = 2.5 \frac{g}{cm^{3}}[/itex]

Dialectic Material 2
ε= [itex]80ε_{0}[/itex]
[itex]U_{d} = .03 \frac{V}{nm}[/itex]
[itex]ρ = 1 \frac{g}{cm^{3}}[/itex]

Dialectic Material 3
ε= [itex]200ε_{0}[/itex]
[itex]U_{d} = .1 \frac{V}{nm}[/itex]
[itex]ρ = 1 \frac{g}{cm^{3}}[/itex]

Metal 1
[itex]ρ=2.7 \frac{g}{cm^{3}}[/itex]

Metal 2
[itex]ρ=2.1 \frac{g}{cm^{3}}[/itex]

The machine which can make the capacitor has the following thickness restrictions
[itex]10 nm < t_{dialectic}< 10 μm[/itex]
[itex]10 μm < t_{dialectic}< 10 cm[/itex]

Equations
[itex]C = \frac{εA}{d}[/itex]
[itex]C = \frac{dQ}{dV}[/itex]
[itex]U = \frac{dW}{dt}[/itex]
the maximum energy stored in a capacitor is below
[itex]w = \frac{1}{2}εCd^{2}U_{d}^{2}[/itex]
[itex]V = U_{d}d[/itex]
[itex]U=CV(t)\frac{dV}{dt}[/itex]
[itex]U=\frac{1}{2}CV^{2}[/itex]
[itex]I=\frac{dQ}{dt}[/itex]
[itex]hp ≈ 746 W[/itex]
[itex]ε_{0} ≈ 8.85*10^{-12} \frac{F}{m}[/itex]
[itex]m = 10^{9} nm[/itex]
[itex]m = 10^{6} μm[/itex]
[itex]m = 10^{3} cm[/itex]
[itex]kg = 1000 g[/itex]

Attempt at a solution
I have no idea how to do this at all or where to begin. I just randomly chose material 3 for the dielectric material and started solving and go the following relations.

C = 3.082644628 F
Q = 678.1818182 C
[itex]w = 10 ε_{0}Cd^{2}[/itex]

I don't know where to go from here or if I'm even on the right track at all. Thanks for any help that anyone can provide. It would be greatly appreciated.

Thanks!
 
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  • #2
Can I post this in the introductory physics forum?
 

1. What is a capacitor?

A capacitor is an electronic component that stores electrical energy in an electric field. It is made up of two conductive plates separated by an insulating material called a dielectric.

2. How do capacitors work?

Capacitors work by storing electrical charge on their plates. When a voltage is applied to the capacitor, one plate becomes positively charged and the other becomes negatively charged. The charge is stored in the electric field between the plates.

3. What are some common uses for capacitors?

Capacitors have many uses in electrical engineering, including filtering and smoothing out power supplies, storing energy in electronic circuits, and coupling signals between different parts of a circuit. They are also commonly used in audio and radio frequency circuits.

4. How do you calculate the capacitance of a capacitor?

The capacitance of a capacitor is calculated by dividing the charge stored on the plates by the voltage applied to the capacitor. It can also be calculated by dividing the area of the plates by the distance between them and the permittivity of the dielectric material.

5. What are some common design problems when working with capacitors?

Some common design problems when working with capacitors include selecting the appropriate capacitance and voltage rating for a specific application, minimizing the effects of parasitic capacitance, and ensuring proper placement and routing of the capacitor in a circuit to avoid interference.

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