Thursday, 26 December 2013

ELECTRONIC DEVICES & CIRCUITS

ELECTRONIC DEVICES & CIRCUITS
1.      Pure semiconductors are poor conductor because all valence electrons are in electron pairs.
2.      Hall effect device can be used to Multiply two signals.
3.      The mobility of electrons in a semiconductor is defined as Drift velocity per unit electric field.
4.      Reverse recovery current in a diode depends on Forward field current.
5.      A tunnel diode is A very heavily doped p-n diode.
6.      A zenor diode works on the principle of tunneling of charge carriers across the junction
7.      IGFET is the other name for MOSFET device.
8.      JFET can be used as Voltage variable resistor.
9.      The gain of bipolar transistor drops at high frequencies. This is because of the Inter-electrode transistor capacitances.
10.  The basic function of buried n+ layer in an n-p-n transistor fabricated in IC is to Reduce the collector series resistance.
11.  Almost all resistors are made in a monolithic integrated circuit During the emitter diffusion.
12.  Why is silicon dioxide layer used in ICs?
Ans: To protect the surface of the chip from external contaminants and to allow for                                             selective formation of the n and p regions by diffusion.
13.  The depletion region of a semiconductor diode is due to Migration of mobile charge carriers.
14.  A LED is basically a forward – biased p-n junction.
15.  A PIN diode is frequently used as a Switching diode for frequencies up to GHz range.
16.  Avalanche photo diodes are preferred over Pin diodes in optical communication systems because of Large power handling capacity.
17.  Transition capacitance can also be called as space charge, barrier depletion layer.

18.  Current caused due to flow of current towards positive terminal is Drift current.

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