Basic Electrical Interview Questions

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Basic Electrical Interview Questions
Basic Electrical Interview Questions

Static electricity refers to the accumulation of electric charge on the surface of materials. It occurs when two objects come into contact, causing electrons to transfer between them, creating an imbalance of charges.

The flow of electric charge, defined as electrons, via a conductor is what we refer to as current electricity. It is the type of electricity used to power devices, as it involves a continuous flow of electrons.

The two types of electrical current are:

The primary sources of electricity include 

Sources of Electricity
Sources of Electricity
  • Fossil fuels (coal, natural gas, oil), 
  • Nuclear energy, 
  • Renewable sources (solar, wind, hydropower, geothermal), and 
  • Chemical energy from batteries.

The main applications of electricity include 

  • Lighting, 
  • Heating, 
  • Cooling, 
  • Communication, 
  • Powering machines, and 
  • Transportation.

A.C. stands for Alternating Current, where the flow of electrons reverses direction periodically. 

It is the type of electricity commonly used in homes and industries.

D.C. stands for Direct Current, where the flow of electrons moves in only one direction. 

  • Batteries and 
  • Electronic devices 

typically use DC.

Conductors are materials that allow the free flow of electric charge, due to the presence of free electrons. 

Ex: Metals like copper & aluminum

Insulators are materials that resist the flow of electric charge, as they have tightly bound electrons that do not move freely. 

Ex: Rubber, Glass, Wood, Oil and Plastic.

Insulators
Insulators
  • Copper, 
  • Aluminum, 
  • Silver, 
  • Gold, and 
  • Brass 

are commonly used conductors.

  • Rubber, 
  • Glass, 
  • Plastic, 
  • Ceramic, and 
  • Mica 

are commonly used insulators.

Dielectric strength is the maximum electric field that an insulating material can withstand without breaking down (or) becoming conductive.

A good conductor should have 

  • High electrical conductivity, 
  • Low resistivity, 
  • High tensile strength, 
  • Thermal conductivity, and 
  • Ductility.

A good insulator should have 

  • High resistivity, 
  • High dielectric strength, 
  • Thermal stability, 
  • Low water absorption, and 
  • Mechanical strength.
Semiconductor
Semiconductor

A semiconductor is an element with electrical conductivity in between a conductor & an insulator. 

Its conductivity can be altered by doping or external influences such as temperature and electric fields.

The two main types of semiconductors are 

  • n-type (negative charge carriers) and 
  • p-type (positive charge carriers).

Resistance is the opposition to electric current flow in a material.

It depends on the 

  • Material, 
  • Length, 
  • Cross-sectional area, and 
  • Temperature of the conductor.

The main classifications of resistance are 

  • Fixed resistance, 
  • Variable resistance (rheostats, potentiometers), and 
  • Non-linear resistance (such as in diodes).

Resistance is measured in ohms (Ω).

A resistor is an electrical component that restricts or controls the flow of electric current in a electrical circuit.

The factors that affect a conductor’s resistance include the 

  • Length of the conductor, 
  • Cross-sectional area, 
  • Material, and 
  • Temperature.

Ohm’s Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. 

Mathematically, 

V=IR

where 

V – Voltage

I – Current, and 

R – Resistance.

Ohm’s Law
Ohm’s Law

Capacitance is the ability of a system to store electrical energy in an electric field, measured in farads (F). 

It is a property of capacitors.

Inductance is the ability of a conductor or coil to store energy in a magnetic field when electrical current flows through it. 

It is measured in henries (H).

The process of converting mechanical energy into electrical energy through the use of electromagnetic induction is referred as generator.