Static Electricity

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Conductors

Allows for the free flow of charge (think charge highway)

Insulators/Dielectrics

Does not allow charges to move (think fly paper)

Charging by friction

rubbing things together, results in one item of each charge

Charging by contact

charge is transferred from a charged object to an uncharged object

Grounding

donating/receiving electrons to establish equilibrium

Coulomb’s Law

the amount of force between two electrically charged particles at rest,
F_E = (k * |q₁| * |q₂|) / r²

Coulomb’s constant

k = 8.99 × 10⁹ (N*m²)/c²

Coulomb

A unit of charge. 1 coulomb = 6×10¹⁸ e^-

Elementary Charge

Charge on a proton or electron, ± 1.6 × 10^-19 c

Capacitance

A characteristic of an object to “store” charge
C = Q/Δv
C = (E_o * A) / d

E_o

8.85 × 10^-12 c² / N*m²

Battery

Component that maintains a potential difference

Ex. a 9V battery has a 9V potential difference

Dielectric Constant

K = C_D / C_o

C_D = capacitance of the substance

C_o = capacitance in vacuum

Dielectric Strength

The maximum electric field the dielectric can handle before “breaking down” and conducting.

DS = Voltage across capacitor / separation of plates, V/m

Max voltage

MV = K * C * DS * d

Electric field

Voltage across the gap that would break down the dielectric, V/m

Farad

F = coulomb / volt = c²/J

Energy stored in a capacitor

E = ½ * Q*V

Capacitance of capacitors in series

1/C = 1/C₁ + 1/C₂ + ….. + C_n

Capacitance of Capacitors in Parallel

C = C₁ + C₂ + ….. + C_n

Max Charge

C_max = C * V_max

Electric Potential

V = (k*Q)/r