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With the increase in temperature if the resistance increases or the current in the circuit decreases then it is said to be have positive temperature coefficient .
But in semi-conductors with the increase in temperature the electrons present in the valance band are excited and they would enter the conduction band for conduction . As the no. of charge carriers always increase in a semi-conductor , implies that the current always increases with the increase in temperature so the semi-conductor can never have positive temperature coefficient
What else can I help you with?
What is the temperature coefficient of an extrinsic semiconductor is?
positive
What happens when the temperature of a forward biased diode is increased?
What happens depends on the temperature coefficient of the diode. If that diode has a positive temperature coefficient, it resistance increases with increased temperature. A diode with a negative temperature coefficient does the opposite.
What is the Tempetature coefficient of an extrinsic semiconductor?
negative
What is the function of a sensistor?
the sensistor functions as a temperature sensitive resistor with a positive coefficient of temperature.used for temperature compensation in various circuits
Why semiconductor has negative temperature coefficient of resistance?
Actually, the BJT is a positive temperature coefficient device. As they get warm, hFe increases, causing more current flow. This can lead to thermal runaway. That is why most class A common emitter configurations use an emitter resistor to place limits on the hFe demand, eliminating thermal drift and runaway.
What is the temperature coefficient of extrinsic semiconductor?
positive
What is the temperature coefficient of an extrinsic semiconductor is?
positive
What is the effect of temperature on hall coefficient of a lightly doped semiconductor?
hall coefficient of a lightly doped semiconductor will decrease with increase in temp as hall coefficient is inversely proportional to number density of charge carriers.
Fullform of ntc and ptc?
ntc: negative temperature coefficient ptc: positive temperature coefficient
Does a safe reactor have a positive or negative 'temperature coefficient of reactivity'?
negative 'temperature coefficient of reactivity'
What is the difference between positive and negative temperature coefficient of resistance?
Negative temperature coefficient of resistance means that as the temperature of a piece of wire or a strip of semiconducting material increases, the electrical resistance of that material decreases.
Why do the semiconductors have negative temperature coefficient whereas the metals have positive values?
Semiconductors: When temperature increases, more electrons jump to conduction band from valance bond. Hence resistance decreases. Metals: Already plenty of electrons are there in conduction band. When temperature increases, the electrons in conduction band of metal vibrate and collide each other during their journey. Hence the the resistance of metal increases with increase of temperature. S.Lakshminarayana
What happens when the temperature of a forward biased diode is increased?
What happens depends on the temperature coefficient of the diode. If that diode has a positive temperature coefficient, it resistance increases with increased temperature. A diode with a negative temperature coefficient does the opposite.
What is the difference between PTC and NTC resistors?
positive temperature coefficient vs. negative temperature coefficient resistance increases or decreases with increase of temperature, respectively.
What is the temperature coefficient of BJT?
No. Semiconductor has negative temp coefficient, because increase in temp causes the increase in the k.e of the electrons bu t not in the no of electrons . these highly energised electronsel increase current, & in terms conductivity.
What is the relationship between resistance and temperature?
• ntc 'negative temperature coefficient': its resistance decreases as the temperature increases• ptc 'positive temperature coefficient': its resistance increases as the temperature increases
Why do conductor have a positive coefficent?
You mean positive temperature coefficient? Yes conductors as they get heated then due to the nucleii vibrating with greater amplitude would have a grip over the moving electrons and so the resistivity increases with the increase in temperature. Hence positive temperature coefficient.
