Electronics

Admission to central universities for UG courses where Chemistry, Electronics, and Instrumentation are main subjects, the candidates must appear for CUET (Common University Entrance Test) 2025. Eligibility demands 50% (40% for SC/ST) in 10+2 in relevant subjects (Physics, Chemistry, and Maths for B.Tech; Chemistry for B.Sc).

Apply for CUET (February-March 2025) by portal NTA, selecting domain subjects like Chemistry, Physics and Mathematics and the general test. Through their portals, universities such as Delhi University, BHU, or JNU, which offer B.Sc or B.Tech in these areas should be applied to for post-CUET results (June 2025 expected). 

A transistor can either be NPN or PNP. It is a three-layer semiconductor device with three terminals—emitter, base, and collector.  In the case of the NPN transistor, there is a larger current from the collector to the emitter due to a small current at the base. It involves an amplification property which is key to the function of the NPN transistor. A transistor can be used in two main modes - as switches in microcontrollers, and computers and as amplifiers in speakers and radios etc. These are foundational in digital and analogue circuits due to their ability to control current. Transistors form the backbone of the integrated circuits and modern electronics.

Energy bands refer to how electrons behave in solids. In the case of conductors where the conductivity is high, the valence band and conduction band overlap which lets the electrons move freely. In the case of semiconductors, the valence and conduction bands have a small energy gap between them such as ?1 eV. There is a requirement for some external energy for electrons to jump to the conduction band. The gap is large in the case of insulators (>3 eV), making the electron movement nearly impossible. The energy band model differentiates how easily a material can conduct electricity. In semiconductors, there is controlled conductivity which is important for electronic devices as in these cases light or thermal energy can excite electrons.