# Lernkarten

Karten 57 Karten 4 Lernende English Andere 14.08.2022 / 10.09.2022 Keine Angabe
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Static vs. Dynamic Electricity

Static: Imbalance of electric charges within or on the surface of a material.

Dynamic: Electrons in motion.

Static dischargers (static wicks)

A plane builds up static electrical charge during the flight by friction between the air and the surfaces of the plane.
--> Static dischargers reduce the build up of static electricity by dispensing the charge into the atmosphere.

Grounding / Bonding

ACFT is statically charged due to...

1. friction between the air and the ACFT surfaces - in-flight
2. friction between the fuel and the fuel pumps, pipes and filters it runs through causes positive charged fuel ions to enter the fuel tank

--> ACFT parts are connected by flexible wire strips to distribute the static charge equally across the whole ACFT to keep it at similar potential.
--> On ground ACFT is grounded to dispose of the static charge

Voltage

= difference of potential
--> On one side there is a surplus of electrons (=Minuspol), on the other side there is a shortage of electrons (=Pluspol)

Current

= electrons per time

Physical current = Movement of electrons from Minuspol to Pluspol
Technical current = Movement of electrons from Pluspol to Minuspol

DC = Direct current --> For low voltage consumers, e.g. PFD
AC = Alternating current --> For high voltage consumers, e.g. generators/motors

Every conductor has a maximum allowable current. --> Depends on the material and cross section

Resistance

= obstruction of the flow of electrons

Depends on...

• Specific resistance of the material $$\rho$$ (Depends on the number of free electrons)
• Lengt L of the conductor (Longer = Higher resistance)
• Cross section A of the conductor (Larger = Lower resistance)
• Temperature
• Metalls: High temperature = higher resistance (and vice-versa)
• Semi-conductors: High temperature = lower resistance (and vice-versa)

Energy / Electrical Work

W = U * I * t [kWh]

Electrical Power

P = W / t = U * I [W]