PS302J2 US Sensor, PS302J2 Datasheet - Page 5

• Manufacturer Part Number: PS302J2
• Description: THERMISTOR 3K OHM +/-0.10 C
• Manufacturer: US Sensor
• Series: PSr

Specifications of PS302J2

• Resistance In Ohms @ 25°c: 3K
• B0/50: 3890K
• Operating Temperature: -80°C ~ 150°C
• Lead Length: 1.50" (38.00mm)
• Mounting Type: Free Hanging
• Package / Case: Bead
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Resistance Tolerance: -
• B Value Tolerance: -
• B25/50: -
• B25/75: -
• B25/85: -
• B25/100: -
• Power - Max: -
• Other names: 615-1001

General Information
NTC and PTC Thermistors
Definition
Thermistors are thermally sensitive resistors whose prime function is to exhibit a large,
predictable and precise change in electrical resistance when subjected to a corresponding change
in body temperature. Negative Temperature Coefficient (NTC) thermistors exhibit a decrease in
electrical resistance when subjected to an increase in body temperature and Positive Temperature
Coefficient (PTC) thermistors exhibit an increase in electrical resistance when subjected to an
increase in body temperature. U.S. Sensor produces thermistors capable of operating over the
temperature range of -100˚ to over +600˚F. Because of their very predictable characteristics and
their excellent long term stability, thermistors are generally accepted to be the most advantageous
sensor for many applications including temperature measurement and control.
Since the negative temperature coefficient of silver sulphide was first observed by Michael
Faraday in 1833, there has been a continual improvement in thermistor technology. The most
important characteristic of a thermistor is, without question, its extremely high temperature
coefficient of resistance. Modern thermistor technology results in the production of devices with
extremely precise resistance versus temperature characteristics, making them the most
advantageous sensor for a wide variety of applications.
A thermistor’s change in electrical resistance due to a corresponding temperature change is evident
whether the thermistor’s body temperature is changed as a result of conduction or radiation from
the surrounding environment or due to “self heating” brought about by power dissipation within
the device.
When a thermistor is used in a circuit where the power dissipated within the device is not
sufficient to cause “self heating”, the thermistor’s body temperature will follow that of the
environment. Thermistors are not “self heated” for use in applications such as temperature
measurement, temperature control or temperature compensation.
When a thermistor is used in a circuit where the power dissipated within the device is sufficient
to cause “self heating”, the thermistor’s body temperature will be dependent upon the thermal
conductivity of its environment as well as its temperature. Thermistors are “self heated” for use in
applications such as liquid level detection, air flow detection and thermal conductivity measurement.
Manufacturing Processes
U.S. Sensor manufactures thermistors using sophisticated state of the art processing techniques.
Their excellent long term stability coupled with precision interchangeability and low cost makes
them ideally suited for temperature sensing applications. The devices are available in a wide
variety of styles designed to suit countless circuit requirements.
NTC Manufacturing Processes
NTC thermistors are manufactured using homogeneous compounds of various metal oxides
including Manganese, Nickel, Cobalt and Copper. The powdered metal oxides, along with
stabilizing agents and organic binders, are combined into exact formulations which will exhibit
certain electrical characteristics upon completion of the manufacturing processes. Dependent
upon the particular application for which the devices are to be used, the oxide/binder
formulation is formed into any number of shapes including chips, discs, wafers and bars.
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