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What happens to the resistance of a material with a positive temperature coefficient when it is heated?
Wiki User
∙ 12y ago
Positive Temperature coefficient indicates that the resistance of material INCREASES with rise in the temperature.
Resistance Temperature COefficient(RTC) is defined as increase in resistance per unit original resistance per unit rise in temperature.
Temperature Coefficient of Resistance=R2-R1/(R1*(T2-T1))
Where:
R2:Resistance at temperature T2
R1:Resistance at temperature T1
SO from formula it is clear that if resistance increases with temperature(T2-T1>0 and R2>R1) then Difference R2-R1 will be positive hence RTC will have positive value. But if with increase in temperature(T2-T1>0) resistance decreases(R2<R1) then difference R2-r1 will be negative hence RTC will be negative.
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoTemperature affects the resistivity of a material which, in turn, affects the resistance of that material. As a general rule, an increase in temperature will cause the resistance of pure metal conductors to rise, and the resistance of most insulators to fall.
The behaviour of resistance due to temperature change is determined by that materials temperature coefficient of resistance, which is positive for pure metal conductors, and negative for most insulators. Knowing the temperature coefficient of resistance enables one to determine the resistance of a material over a wide range of temperature variations.
Wiki User
∙ 11y agoHeat and resistance is directly proportional, in that, when heat goes up, resistance goes up. An example of this is the 'ping' effect when a worn old style incandescent bulb blows 95% of the time when it's energised, not when it's been on for a while. This is because the resistance of the filament is low/cold & allows greater current to flow.
AnswerIt depends on the conductor. For most metal conductors, if the temperature is increased, there is an increase in resistance; some more than others (tungsten, for example, far more so than, say, copper). For some metal alloys, such as constantan, the temperature may have very little effect on their resistance. For carbon, as the temperature increases, its resistance decreases.
It all depends upon the material's temperature coefficient of resistance.
Wiki User
∙ 13y agoIf we increase the temperature of a conductor, its resistance will increase. In a semiconductor, resistance will decrease as temperature increases.
Wiki User
∙ 12y agoIt increases
Wiki User
∙ 10y agoit decreases
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What is the difference between the sensistor and thermistor?
Thermistor: Negative temperature coefficient Sensistor: Positive temperature coefficient.
What happen to the resistance of metallic wire if it is heatedExplain?
Its resistance increases. This is because of vibrations of the core of atoms and so they have got good influence over the movement of electrons. So conductivity gets reduced and so resistance increases. This is what we call positive temperature coefficient
What is the difference between thermostat and thermister?
Thermostat is a mechanical device that reacts to heat. As heat is applied the thermostat contracts and allows water to flow through the system. A thermistor is a thermal resistance sensor that also reacts to heat. There are two kinds, one is a negative coefficient and is a positive coefficient. As heat increases it changes the resistance value of the thermistor. That resistance value is transmitted to the computer and/or temperature gauge. Through computation the computer can can tell what temperature the engine is at to make decisions on how it should be run.
Does a high temperature wire have more resistance?
Ideally, an electrical fuse should not have a high resistance. It will generally have some, because the way most cartridge fuses work is by heating a thin filament to the melting point when a certain current flows through it. The heating is resistive heating, which is given by the equation P = I2R, or power = the square of the current times resistance. <> The above is 100% correct, I just want to add: A fuse does not reduce the power in any way, It simply does not allow too much power to be taken. Example: You can use A 100amp fuse on A 10amp motor, The power supply will be 10amps because that's all the motor requires, but if there is a short or the motor is over worked the fuse will allow more chance of damage because its way too big for the job. Another: If A 10amp fuse is used to protect A 100amp motor the motor will blow the fuse everytime its terned on, because the fuse will not allow the motor the necessary power to opperate.
What is the critical temperature at which nuclear reactions begin?
For nuclear fission reactors there is no critical temperature, though they do have a temperature coefficient which makes the efficiency of the chain reaction vary slightly with temperature. This can be negative or positive, obvously a negative coefficient is preferred and is safer. Nuclear fusion is another matter, and very high temperatures are required in tokamaks to get fusion started
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.
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
How the resistance of conducting material vary with temperature?
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
Do The resistance of a material generally increases as its temperature increases?
The answer to this depends on the material from which the resistance is made. For most materials resistance increases with increasing temperature. This is referred to as having a "positive temperature coefficient". Some materials have a negative temperature coefficient; these do have uses in electronics.
What is the temperature coefficient of resistance?
The temperature coefficient of resistance is a number used to predict how the resistance of a material changes with changes in temperature. Typically the units are either resistance per temperature or 1/temperature depending on which equation is used for the calculations. For example, in copper the temperature coefficient of resistance is about 0.0039 per change in degrees Celsius. A positive temperature coefficient of resistance means that the resistance of the material will increase as temperature increases. As per the equation or say unit of resistance temperature coefficient, its definition can be given as below: " Rise in temperature per unit initial resistance, when temperature is raised by one degree Celsius is called the resistance temperature coefficient."
Why does the resistance of a thermistor change when you change its temperature?
The resistance of a thermistor changes when its temperature changes due to the inherent properties of the thermistor material. In a negative temperature coefficient (NTC) thermistor, the resistance decreases as the temperature increases, whereas in a positive temperature coefficient (PTC) thermistor, the resistance increases as the temperature rises. This change in resistance is caused by the variation in the number of charge carriers (electrons or holes) and their mobility within the material as temperature changes.
If a carbon resistor increases in temperature its resistance will?
This depends on the type of conductor. If the conductor has a positive coefficient the resistance will increase. If the conductor has a negative temperature coefficient the resistance will decrease.
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 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.
Why does the resistance of a thermistor decrease as the temperature rises?
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.
What sort of a sensor is a PT100?
A PT100 is a PTC (Positive Temperature Coefficient), which means that it's resistance ascends with it's temperature
What happens to its resistance when an electrical device is heated?
That will depend on the temperature coefficient of resistance of the device, which could be positive (i.e. resistance increases with increasing temperature), negative (i.e. resistance decreases with increasing temperature), or zero (i.e. resistance is unaffected by temperature changes).
