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
The resistance of the semiconductor material decreases with increase in temperature,this phenomenon is said to be negative temperature coefficient of semiconductor.
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.
Actually it depends on the material from which the resistor is made, well in general for all practical purposes we choose a material with positive temperature coefficient as we deliberately want to add a resistance to the circuit. But if we come across some resistors which are made up of materials like Glass, Ceramics, Semiconductors , have negative temperature coefficients (practically not used)
negative tempareture It depends on the reverse voltage. Up to about 5.6 volts, the zener has a negative temperature coefficient. Beyond 5.6 volts it begins to show a positive temperature coefficient.
Well, there's typically two types of materials-Those with positive temperature coefficient and those with negative temperature coefficient. Positive temperature coefficient are those whose resistance increases as temperature increases. Negative temperature cofficient are those whose resistance decrease when the temperature increase. There are however some alloys such as Manganin& Constantan whose resistance is not affected by temperature
• ntc 'negative temperature coefficient': its resistance decreases as the temperature increases• ptc 'positive temperature coefficient': its resistance increases as the temperature increases
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.
negative 'temperature coefficient of reactivity'
Semiconductors such as silicon, germanium and gallium arsenide (GaAs) have negative temperature coefficient.
ntc: negative temperature coefficient ptc: positive temperature coefficient
Actually it depends on the material from which the resistor is made, well in general for all practical purposes we choose a material with positive temperature coefficient as we deliberately want to add a resistance to the circuit. But if we come across some resistors which are made up of materials like Glass, Ceramics, Semiconductors , have negative temperature coefficients (practically not used)
negative tempareture It depends on the reverse voltage. Up to about 5.6 volts, the zener has a negative temperature coefficient. Beyond 5.6 volts it begins to show a positive temperature coefficient.
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.
positive temperature coefficient vs. negative temperature coefficient resistance increases or decreases with increase of temperature, respectively.
Well, there's typically two types of materials-Those with positive temperature coefficient and those with negative temperature coefficient. Positive temperature coefficient are those whose resistance increases as temperature increases. Negative temperature cofficient are those whose resistance decrease when the temperature increase. There are however some alloys such as Manganin& Constantan whose resistance is not affected by temperature
• ntc 'negative temperature coefficient': its resistance decreases as the temperature increases• ptc 'positive temperature coefficient': its resistance increases as the temperature increases
As carbon filament bulbs have a negative temperature coefficient and tungsten filament light bulbs have a positive temperature coefficient.
Some materials have negative temperature coefficients of resistance, and some have positive temperature coefficients. Carbon is an example of a substance with a negative thermal coefficient of resistance, so it's resistance will decrease as it gets hotter.