answersLogoWhite

0

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.

User Avatar

Wiki User

11y ago

What else can I help you with?

Continue Learning about Engineering

How does resistivity depends on temperature of conductors?

The resistance of a simple conductor normally rises as its temperature rises.


Does the resistance of heater coil remains same when current flows through it?

Typically resistance rises with temperature.


Does base direct current increase or decrease with temperature?

The base direct current (DC) in semiconductor devices generally increases with temperature. As temperature rises, the thermal energy allows more charge carriers to become available, which enhances conductivity and increases current flow. However, excessive temperature can lead to increased resistance and potential device failure, so there is a limit to this trend. In contrast, for some materials, such as metals, resistance typically increases with temperature, which can decrease the current if voltage remains constant.


What will happen too amperage if voltage is increased and resistance remains the same?

Ohms Law says Voltage = Current x Resistance. Hence if voltage rises, so will current.


Why the slope of voltage-resistance characteristic increases in the case of tungsten lamp and decresing in case of carbon lamp?

If the filament really was made from a material that has a negative temperature coefficient (as temperature increases, resistance decreases) then the decreasing resistance would cause more and more current to be taken as the lamp heated up and the temperature would get higher and higher in a runaway manner until either the power supply's breaker would trip or (more likely) the light bulb's filament would simply burn open. In fact the filament has to be made from a material that has a positive temperature coefficient. (As temperature increases, resistance increases.) Then, as the bulb's temperature rises, its filament's increasing resistance causes less current to be taken than when it was cold. Quite quickly a stable "steady-state" temperature and "running" resistance is reached so that the bulb simply continues to give out a steady amount of light according to the current it is taking from the electricity supply.

Related Questions

How the temperature of a thermistor affect the current which is able to flow in the circuit?

According to the different coefficient of resistance change, thermistors are divided into two types: positive temperature coefficient thermistor (PTC), whose resistance value increases with increasing temperature, and negative temperature coefficient thermistor Resistance (NTC), whose resistance value decreases with increasing temperature. We're JYH HSU(JEC) Electronics Ltd (or Dongguan Zhixu Electronic Co., Ltd.), an electronic components manufacturer. You may google search "JYH HSU" to find our official website.


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.


What is a negativ temperature co-efficient?

A negative temperature coefficient (NTC) refers to a type of thermistor where the resistance decreases as the temperature increases. This means that as the temperature rises, the electrical resistance of the NTC thermistor decreases, allowing more current to flow through it. NTC thermistors are commonly used in temperature sensing and compensation applications.


What is the working principle of the thermistor?

A thermistor changes it's resistance depending on temperature. Hence Thermal-Resistor. (Thermistor) It is all to do with the crystal structure of the substance the thermistor is made of. Some increase their resistance as temperature rises, called Positive Thermal coefficient, 'PTC'. Others reduce their resistance with increasing temperature, called Negative Thermal Coefficient. 'NTC'. They can be used in a feedback loop of a simple amplifier and switch circuits, to control temperature of a device. They can be calibrated for use in a current loop, to directly measure temperature, like a thermometer. They can be used to stop surges in start up circuits, initially giving a high resistance until things warm up. Or used to apply a large current and then reduce as things warm up. (Like in the old degaussing coils on a colour CRT).


How does temperature affect the resistance of conducting materials?

As temperature increases, the resistance of conducting materials also typically increases. This is because as temperature rises, the atoms in the material vibrate more, leading to more collisions with electrons, which in turn increases resistance. Conversely, as temperature decreases, resistance tends to decrease as well.


How does resistivity depends on temperature of conductors?

The resistance of a simple conductor normally rises as its temperature rises.


How thermistors work?

A thermistor changes it's resistance depending on temperature. Hence Thermal-Resistor. (Thermistor) It is all to do with the crystal structure of the substance the thermistor is made of. Some increase their resistance as temperature rises, called Positive Thermal coefficient, 'PTC'. Others reduce their resistance with increasing temperature, called Negative Thermal Coefficient. 'NTC'. They can be used in a feedback loop of a simple amplifier and switch circuits, to control temperature of a device. They can be calibrated for use in a current loop, to directly measure temperature, like a thermometer. They can be used to stop surges in start up circuits, initially giving a high resistance until things warm up. Or used to apply a large current and then reduce as things warm up. (Like in the old degaussing coils on a colour CRT).


Does the rate of water evaporation increase or decrease as temperature rises?

As temperature rises, the rate of water evaporation increases.


Does air become lighter as the temperature rises?

noThe density decrease when the temperature increase.


What is the relationship between resistance and temperature in electrical circuits?

In electrical circuits, the resistance of a material typically increases as its temperature rises. This relationship is known as temperature coefficient of resistance.


Why in a wire the hotter it is the less resistance?

In a wire, as the temperature increases, the atoms in the wire vibrate more rapidly, which causes more collisions with the flow of electrons, increasing resistance. However, in some materials like metals, as temperature rises, the atoms also move farther apart, which can offset the increase in collisions, leading to a net decrease in resistance. This is known as the positive temperature coefficient of resistance.


Does resistance of heater coil remains same when current flows through it?

Typically resistance rises with temperature.