eee-1109 ECE-1109 Introduction to ECE
Core Definitions Found Explicitly in Previous Year Questions (PYQs)
Energy Band
When ‘n’ isolated atoms are brought close, the outer orbit splits into the valence band and the conduction band; this set of close or very close spaced energy levels is called the energy band. *2018, 2019, 2021, 2023, 2024
Valence Band
The highest energy band in a solid that is completely filled or partially filled with electrons at absolute zero temperature. Electrons here are involved in chemical bonding. *2018, 2019, 2021, 2023, 2024
Conduction Band
The energy band situated above the valence band; it is the band of the next higher permitted energy level. Electrons in this band are free to move and conduct current. *2018, 2019, 2021, 2023, 2024
Forbidden Band (Band Gap, E_g )
The energy gap between the valence band and the conduction band where no electron can exist in a solid. *2018, 2019, 2021, 2023, 2024
Intrinsic Semiconductor
A pure semiconductor material with no intentional impurities. Its conductivity arises solely from thermally generated electron-hole pairs (EHPs). *2023
Extrinsic Semiconductor
A semiconductor obtained by adding a small and controlled amount of impurity atoms (dopants) to increase conductivity. *2023
Drift Current
The movement of charge carriers (electrons and holes) under the influence of an external electric field. *Used contextually in 2016, 2017, 2022, 2024 (P-N Junction operation)
Diffusion Current
The movement of carriers due to a non-uniform carrier concentration gradient, where carriers tend to move from regions of high concentration to low concentration. *Used contextually in 2016, 2017, 2022, 2024 (P-N Junction operation)
Depletion Layer
The zone around a p-n junction where mobile charge carriers are absent due to recombination, leaving behind immobile ionized donor (positive) and acceptor (negative) atoms. *2015, 2016, 2018, 2019, 2020, 2021, 2022
Zener Breakdown
Occurs in heavily doped diodes with a thin depletion region; the strong electric field causes electron tunneling. 2015, 2017, 2018, 2021, 2022, 2024
Zener Region
The region in the reverse characteristic curve where the Zener diode operates reliably. *2019, 2022, 2024