UDT 2012, BDT 2012,Cat 2012-99.78, Converts- IIM C,IIM L,FMS. Wl-XL. Rejects-IIM A.
yeh dekho .. not sure how much it'll help
I am in no position to explain any acads to a panel .. only know basic phenomena behind these devices
1. Explain the working of a diode.
Diodes are devices that allow current to flow in one direction but oppose flow in the reverse direction. Could restate it as having low resistance in one direction/ high resistance in opposite. Most common forms of diodes are LEDs, Zener diodes, p-n junction diodes.
LEDs when biased have carriers re-combining. This results in them reaching lower/more stable energy states from their earlier states when they were separated. The energy released when reaching the more stable states is seen in the form of EM radiation of different frequencies .. this can be blue/red/UV/IR ..
p-n junction diodes contain two separate regions of semiconductor material doped differently to setup the p/n regions. They aren't joined together. The junction is where a depletion region is created by the re-combination of holes and electrons. This is what allows carriers to flow through easily in one direction and opposes the flow in the opposite.
Zener diode is an extension of this in that it will allow current to flow in the opposite direction at a reduced reverse biased voltage. This is where it is used to protect circuits. The phenomeon is Zener breakdown where a voltage difference over the small depletion region results in a large electric field which pulls out carriers in the opposite direction ( something similar to corona discharge, lightning .. might be an oversimplification .. ). Avalanche breakdown is also similar to this and both phenomenon occur at the same time. The difference between the two diodes is that ADs maintain a small voltage across them in breakdown but ZDs don't. Not very sure about this in more detail ..
Schottky diodes are also somewhat similar to p-ns but they have additional metal/silicon junction that gives faster switching times ... you could mention bias voltages of diodes .. silicon 0.7V, germanium 0.3V, SD 0.15V etc ..
2. Explain Zener diode, knee voltage, breakdown voltage. Applications.
Breakdown voltage is that voltage at which an insulator starts conducting. The limit in Zener diodes is Zener voltage .. avalanche point and all such terms are similar to this. Insulating material is ionized by application of strong voltage. Avalanche in diodes, Corona in fluids, Lightning/sparks in air ..
ZDs could be used to protect circuits from unexpected surges by placing them in reverse bias .. When a surge happens, it will breakdown because of its design easily, allow current to pass through it easily, protect the circuit. Current won't flow through the circuit because it will offer more resistance to current than your reverse biased ZD ..
3. Explain Impatt, Schottky, and Tunnel diode. Applications.
IMPATT, Tunnel used in high frequency electronics. iske aage jyada nahi pata ..
IMPATT uses the fact that an electron when accelerated to impact an atom can knock out an electron from it ... thus causing an avalanche effect
Tunnel diodes have a very thin p-n junction that allows quantum tunneling to kick in ..
iske jyada kahan kaise use hota hai .. pata nahi .. TBH never studied about them in any detail ..
5. What are Flip Flops?
Basic elements of memory .. bistable electronic device .. state can be controlled either by changing the level of input ( as in latches ) or my the edge of the input ( as in flip flops ) .. mostly basic wikipedia stuff ..
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