Explanation
As temperature increases saturation current also increases.
Grid is maintained between 0 volt to certain negative voltage.
In diode the output is in same phase with the input therefore it cannot be used to built NOT gate.
In common emitter transistor amplifier current gain β > 1, so output current > input current, hence Assertion is correct.
Also, input circuit has low resistance due to forward biasing to emitter base junction, hence Reason is false.
In forward biasing of PN junction current flows due to diffusion of majority charge carriers. While in reverse biasing current flows due to drifting of minority charge carriers.
The circuit given in the reason is a PNP transistor having emitter more negative w.r.t. base, so it is reverse biased and collector is more positive w.r.t. base, so it is forward biased.
In semiconductors the energy gap between conduction band and valence band is small ( ≈ 1 eV). Due to temperature rise, electron in the valence band gain thermal energy and may jumpy across the small energy gap, (to the conduction band). Thus conductivity increases and hence resistance decreases.
The ratio of the velocity to the applied field is called the mobility. Since electrons arc lighter than holes, they move faster in applied field than holes.
The energy gap for germanium is less (0.72 eV) than the energy gap of silicon (LI eV). Therefore, silicon is preferred over germanium for making semiconductor devices.
We cannot measure the potential barrier of a PN-junction by connecting a sensitive voltmeter across its terminals because in the depletion region, there are no free electrons and holes and in the absence of forward biasing. PN-junction offers infinite resistance.
The energy gap between valence band and conduction band in germanium is 0.76 eV and the energy gap between valence band and conduction band in silicon is 1.1 eV. Also, it is true that thermal energy produces fewer minority carriers in silicon than in germanium.
Two PN-junctions placed back to back cannot work as NPN transistor because in transistor the width and concentration of doping of P-semiconductor is less as compared to width doping of N-type semiconductor type.
Common emitter is preferred over common base because all the current, voltage and power gain of common emitter amplifier is much more than the gains of common base amplifier.
In PN-junction, the diffusion of majority carriers takes place when, junction is forward biased and drifting of minority carriers takes place across the function, when reverse biased. The reverse bias opposes the majority carriers but makes the minority carriers to cross the PN-junction. Thus the small current in µA flows during reverse bias.
These gates are called digital building blocks because using these gates only (either NAND or NOR) we can compile all other gates also (like OR , AND, NOT, XOR).
Potential difference across the resistance is zero, because diode is in reverse biasing hence no current flows.
When the reverse voltage across the zener diode is equal to or more than the breakdown voltage, the reverse current increases sharply.
In vacuum tubes, vacuum is necessary and the working of semiconductor devices is independent of heating or vacuum.
Number of holes in base region increases hence recombination of electron and hole are also increases in this region. As result base current increases which in turn decreases the collector current.
Pure Cu is already an excellent conductor, since it has a partially filled conduction band, furthermore, Cu forms a metallic crystal as opposed to the covalent crystals of silicon or germanium, so the scheme of using an impurity to donate or accept an electron does not work for copper. In fact adding impurities to copper decreases the conductivity because an impurity tends to scatter electrons, impeding the flow of current.
Charge carriers inside the P-type semiconductor are holes (mainly). Inside the conductor charge carriers arc electrons and for cell ions are the charge carriers.
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