ST1R030BRA US Sensor, ST1R030BRA Datasheet - Page 9

• Manufacturer Part Number: ST1R030BRA
• Description: CURRENT LIMITER INRUSH 1 OHM 30A
• Manufacturer: US Sensor
• Series: STr

Specifications of ST1R030BRA

• R @ 25°c: 1.0 Ohm
• R @ Current: 0.015 Ohm
• Current - Steady State Max: 30A
• Tolerance: ±20%
• Diameter: 1.25" (31.8mm)
• Lead Spacing: 0.31" (7.87mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 615-1047; ST1R030B

Terminology
Zero-Power Resistance (R
)
T
The zero-power resistance is the dc resistance value of a thermistor measured at a specified
temperature with power dissipated by the thermistor low enough that any further decrease in
power will result in not more than 0.1 % (or one-tenth of the specified measurement tolerance,
whichever is smaller) change in resistance.
Resistance Ratio Characteristic
The resistance ratio characteristic identifies the ratio of the zero-power resistance of a thermistor
measured at 25˚C to that resistance measured at 125˚C.
Zero-Power Temperature Coefficient Of Resistance (alpha
)
T
Zero-power coefficient of resistance is the ratio at the specified temperature (T) of the rate of
change of zero-power resistance with temperature to the zero-power resistance of the thermistor.
1 ___
(D R
)
______
T
=
T
R
(D T)
T
Negative Temperature Coefficient (NTC)
An NTC thermistor is one in which the zero-power resistance decreases with an increase in
body temperature.
Positive Temperature Coefficient (PTC)
A PTC thermistor is one in which the zero-power resistance increases with an increase in
body temperature.
Maximum Operating Temperature
The maximum operating temperature of a thermistor is the maximum body temperature at
which the thermistor will operate for an extended period of time with acceptable stability of
its characteristics. This temperature can be the result of internal or external heating, or both,
and should not exceed the maximum value specified.
Maximum Power Rating
The maximum power rating of a thermistor is the maximum power which a thermistor will
dissipate for an extended period of time with acceptable stability of its characteristics.
Dissipation Constant
The dissipation constant is the ratio, (expressed in milliwatts per degree C) at a specified
ambient temperature, of a change in power dissipation in a thermistor to the resultant body
temperature change.
Thermal Time Constant
The thermal time constant is the time required for a thermistor to change 63.2 % of the total
difference between its initial and final body temperature when subjected to a step function
change in temperature under zero-power conditions.
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