Semiconductor Types and Theory

Why is silicon preferred over germanium in modern semiconductor applications?

It maintains stability across a wider range of temperatures

In pure silicon, why does the material act as an insulator?

All outer shell electrons are locked in covalent bonds

Which impurity type creates an N-type semiconductor?

Arsenic

Why are multiphase inverters lighter than single-phase types of the same rating?

They distribute current across multiple coils

A permanent magnet rotary inverter produces AC by:

Rotating a magnet within stator coils to induce voltage

In an N-type semiconductor, the majority current carriers are:

Electrons

Which inverter type adjusts flux paths using soft iron laminations?

Inductor-type rotary inverter

The primary role of rectifiers in aircraft is:

Transforming AC to DC

The process of intentionally adding impurities to a semiconductor is called:

Doping

What makes a zener diode unique compared to a rectifier diode?

It conducts at a defined reverse bias voltage

Why are larger rectifier diodes encased in metal?

To provide heat sinking for high current loads

Which statement correctly contrasts diode biasing?

Forward bias = low resistance; Reverse bias = maximum resistance

Why are holes considered "positive charges" in P-type material?

They represent missing electrons that appear to move opposite electron flow

In reverse bias, what is the most noticeable effect?

Widened depletion zone

In forward bias, current flows because:

The applied voltage reduces the barrier field

A major advantage of static inverters in aircraft is:

Ability to operate without moving parts

What determines the frequency of a revolving armature inverter?

Motor speed and number of poles

Which best describes electron behavior in forward bias?

They recombine with holes at the junction and continue as valence electrons

Inverters in aircraft systems serve what main function?

Convert DC power to AC for avionics and instruments

How does a full-wave rectifier differ from half-wave?

It flips negative alternations positive, producing continuous pulses

Why are Schottky diodes faster than bipolar diodes?

They lack a depletion zone and charge storage

What is the significance of the depletion region in a PN junction?

It forms a barrier preventing further carrier crossing

In a half-wave rectifier, why is the negative swing absent in the output?

The diode blocks current when reverse biased

When a diode is unbiased, what causes equilibrium to occur?

Depletion zone ions preventing further carrier movement

Why does current not flow in reverse bias?

Electrons and holes are drawn away from the junction