JEE · Physics · Semiconductor Electronics (Diodes) doubts
8 doubts found
How does a diode turn AC into DC (rectification)?
A diode conducts only when forward-biased, so it passes current in just one direction.
Why is a Zener diode used to keep a voltage steady (as a regulator)?
A Zener diode is designed to operate in reverse breakdown, where its voltage stays almost constant over a wide range of current.
Why does an LED light up but only when connected the right way round?
An LED is a p–n junction that emits light when forward-biased: electrons and holes recombine across the junction and release the energy as photons, with the colour set by the semiconductor's band gap.
What actually happens inside a p–n junction the moment you forward-bias it?
At rest, a depletion region with a built-in barrier stops most carriers crossing.
What does “Forward & reverse bias” actually mean in Semiconductor Electronics (Diodes), and why does it matter for JEE?
forward bias (p to +, n to −) lowers the junction barrier and lets current flow; reverse bias widens the depletion region and blocks it.
I keep getting “Forward & reverse bias” questions wrong in Semiconductor Electronics (Diodes). What's the trap?
thinking a diode conducts equally both ways.
What does “Depletion region” actually mean in Semiconductor Electronics (Diodes), and why does it matter for JEE?
the charge-free zone at a p–n junction that sets up a built-in barrier potential.
I keep getting “Depletion region” questions wrong in Semiconductor Electronics (Diodes). What's the trap?
thinking the depletion region has free charge carriers.