BharatNotes Diode
noun (also used attributively/adjectivally, as in "diode valve")Usage in a UPSC answer
Much like a diode in an electrical circuit, an unaccountable bureaucracy can permit power to flow downward as directives while resisting the upward flow of grievance and feedback, and it is precisely this one-way conductance that participatory governance reforms seek to break.
Synonyms
Antonyms
Word Family
diode (n), diodes (n pl), diodic (adj)
Root
Coined/Modern (1919, W.H. Eccles): Greek di- = two; hodos = way, passage — two-terminal device
Etymology
Coined in 1919 by William Henry Eccles from Greek di- (two) + hodos (way, passage).
Memory Hook
DI- (two) + -ODE (from electrODE) = a two-electrode device; picture a one-way street sign letting current pass only DIrectly forward, never back.
How This Word Works in UPSC Writing
A two-terminal device that conducts current in one direction only, built on a p-n junction. Under forward bias the depletion region at the junction narrows and current flows; under reverse bias it widens and current is blocked, and that asymmetry is the whole of the device's usefulness. Its primary job is rectification, converting alternating current into direct current, which is what happens inside every phone charger and power supply, a single diode giving half-wave rectification and four arranged in a bridge giving full-wave. The variants are worth distinguishing because each reverses or exploits a different part of the same physics: a light-emitting diode releases energy as light when charge carriers recombine, a photodiode and a solar cell run the process the other way by generating current from incident light, and a Zener diode is designed to conduct in reverse breakdown at a fixed voltage and so is used to regulate supply.
Don’t Confuse It With
A diode conducts in one direction only, while a resistor limits current equally in both. The p-n junction is the structure creating that asymmetry and the depletion region is the charge-free zone formed at it. Forward bias narrows the depletion region and permits conduction, while reverse bias widens it and blocks. Rectification, the conversion of alternating current to direct, is what a diode does, and is not to be confused with amplification, which needs a transistor.
Hindi Meaning
डायोड; दिष्टकारी (dishtkārī) for rectifier.
Common Questions
- What does a diode do?
- It allows electric current to pass in one direction only, which makes it the basic component used to convert alternating current into direct current.
- What is the difference between forward and reverse bias?
- Forward bias narrows the depletion region at the junction so current flows, while reverse bias widens it so current is effectively blocked.
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