Electronics

have a very weak conductivity => after a certain contamination a certain voltage is attained

conductivity = the electrons in the outermost shell of the material determine its electrical conductivity

have many electrons in the outermost shell (3 to 8) => no free electrons => The electrical resistance is almost infinite

Bohrs model => greater the distance of the electron from the core, the greater is the energy level of the electron => quantum jump from on to another orbit

=> The light effect by the quantum jump can be produced withe different material

=> fall back to a lower orbit and emit photons of light, which can be seen as visible light 

Inside: either a cave or low pressure inert gas => The heating of the filament causes it to emit light and the vacuum/inert gas prevents the filament from burning out due to evaporation

the glass tube, which contains two electrodes at each end and a gas => both electrode filaments very quickly and emits electrons to ionize the argon gas inside the tube ==> ignites the gas with a very high voltage

two semiconductors layers=> low voltage electrons are moved from one semiconductor material to another semidconductor material => In the penetration (Durchdringung) of the other semiconductor material light photons are generated ==> High efficiency low pr

a magnetic field rotates inside a conductor loop and produces an alternating voltage => When a load is connected to the conductor loop, an AC results

the chemical effect of electricity is used to produce voltage => two different solid conductors are submerged on a liquid conductor

a changing mechanical load => crystals produce a voltage proportional to the change in geometric dimension => this is a reversible process => clocks, watches

between aircraft fuselage can generate large sparks (Funken ) => can affect communications and navigation systems

two different metals are connected and heated at the junction ==> very low voltage is produced

Spannung (V) the relation of the work (w) necessary to move a charge (lauding) to the magnitude of this electrical charge (Q)

=> \(U = {W \over Q}\)

=> pole with a shortage of electrons is called positive (+)

=> pole with a surplus of electrons is called negative (-) 

der Fluss = Spannung => (A) => is directed movement of electrical charge => rleation quarge to time

=> \(I = {Q \over t}\)

=>Current flow must be from the electron superplus (-) to the lectron shortage (+) 

Wiederstand (R) => electrons exchange their energy => in this way, electrical energy is transformed into heat

Depends on:

a) resistance of the material

b) teh length

c) section 

a) Evaporated carbon resitor => thinner layers provide greater resistance

b) Metal resistor: alloys are wounded around a small porcelain tube => the cros section of the conductor and the length of the wire  

c) Variable esistor => manually controllable = potentiometer

d) Temperature Dependence => 3 types: PTC, constant and NTC resistance of every resistor changes with temperature

Variable resistor => manually controllable resistor z.B. VHF 

The value of the resistor remains constant with the temperature change => used as a balancing resistor in temperature measurement circuit

Positive Temperature coefficient Resistor: resistance increase with increasing temperature

Negative Temperature Coefficient Resistor: resistance decreases as the temperature increases => 2 Drähte ( innen + aussen Halbleitermaterial, ganz aussen die Masse) wenn es heisser, nimmt Resistance ab und wandert an die Masse = electrical Fluss = Signal

a closed circuit => DC electrical circuit => No change in the amount of current over time in a DC circuit = I = constant = no change in the direction of the current

AC current means a change in the direction of the current

switch multiple independent circuit

switch multiple independent circuit => Connection over many switches !!

Same principle as the toggle Switch but there ate 3 positions and instead of toggle they work with a broker action ==> A und B or B and C or nothing

ziehen

a) Bimetallci switch

b) Time switch

c) Reed switch 

two different metals with different coefficient of expansion are fixed together => moves up or down if the temperature changes => temperature changes are converted into a mechanical displacement => used in circuit brakes

automatic switches which switch their contacts on or off after a certain some ==> starter logical of an APU

use two or three metal strips (called reed) => have plated contact at their tips => in a glass tube filled with inert gas => a A field fro a permanent magnet or an electromagnet deflects the reed, closing or opening the switch contact => normally open

=> three reeds: a pair of normally opened and normally closed contacts 

Sicherungen => one fuse as malted, it has to be replaced => melting when current to high

Circuit braker  ( ==> all thermal circuit brakers )

a) Push (stossen) type cirvuit braker

b) Push (stossen) pull type cirvuit braker

c) Toggle switc type cirvuit braker

two plates of different metals => it current to high => CB opens ==> thermal circuit breakers

most common => example by gear failure => that it can be extended manually, its circuit breaker must be pulled ==> thermal circuit breakers