Temperature Coefficient Of Wire Wound Resistor

The tolerance level may be there from 5 to 10. The resistors also need a low temperature coefficient of resistance must be low possibly 5 ppm 0c.

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The temperature coefficient of resistance or tcr is one of the main used parameters to characterize a resistor.

Temperature coefficient of wire wound resistor. The wire wound resistor has a resistance which varies from 1 ohm to 1 mega ohm and power dissipation may vary from 5 watt to 250 watt. Following are the disadvantages of carbon resistor. The temperature coefficient of resistance lies around 5 ppm0c which is considerably better than most metal film resistors around 25 ppm0c.

Long term stability should also be low possibly less than 40 ppm per year. The tolerance level may be there from 5 to 10. With figures like these basic resistance tolerance levels of 001 can be chosen.

That means its resistance will not change more than 0000020 ohms 201000000 per ohm per degree centigrade temperature change within the rated temperature range of 55 to 1450c measured from 250c room temperature assume our resistor is in a product that heats up from room temperature to 500c. The tcr defines the change in resistance as a function of the ambient temperature. The alpha a constant is known as the temperature coefficient of resistance and symbolizes the resistance change factor per degree of temperature change.

Using this high value resistor can easily be made. The temperature coefficient of resistance of manganin and constantan is almost zero. Current carrying capacity and hence power wattage is limited to about 2watts.

Thin film resistors are usually far more expensive than thick film resistors. Typical values for the tolerance of the resistance value is 01 or better. In wire wound resistor a wire of manganin or constantan is wound around a cylinder of insulating material.

The common way to express the tcr is in ppm0c which stands for parts per million per centigrade degree. Resistance value get changed by change in temperature humidity etc. High precision wire wound resistors typically used in precision af attenuators measuring bridges and calibration equipment.

All the resistors value of resistance is specified at specific temperature and that is 20 degree celsius. Temperature coefficients of thick film resistors are high typically 200 or 250 ppmk. Temperature coefficient of resistance this is the factor that temperature does affect the value of resistance in a resistor or a conducting wire.

A 40 kelvin 70 0f temperature change can change the resistance by 1. So resistance variation with temperature of these resistors is negligible. It has low temperature coefficient value.

Just as all materials have a certain specific resistance at 200 c they also change resistance according to temperature by certain amounts.