Surge-Arrestor Negative Temperature Coefficient Thermistor
SCNxxD-11 Series
Outline
This is a Negative Temperature Coefficient Resistor
Whose
resistance
changes
with
ambient
temperature
changes.Thermistor comprises 2 or 4 kinds of metal oxides of
iron,nickel,cobalt, manganese and copper, being shaped and
sintered at high temperature(1200
℃
to 1500
℃
).
Features
Small in size,high-powered, and very capable of
bringing down the surge current;
Quick in reaction;
High in B value and low in residual current;Long service
life and high reliability;High coefficient of safety and wide
range of application.
Applications
Conversion power supply, switch power, UPS power,
Kinds of electric heater, electronic energy-saving lamps,
electronic ballast etc all kinds of power circuit protection of
electronic equipments, filament protection of CRT, bulb and
other lighting lamps.
Part Number Code
SCN
(1)
10
(2)
D - 11
(3)
(1) SCN: Socay Negative Temperature Cofficient Resistor.
(2) 10: Resistance Value:10Ω.
(3) D-11: Diameter of Chip: Φ11.
SOCAY Electronics Corp., Ltd.
Revision December 08, 2016
www.socay.com
1/3
@ SOCAY Electronics Corp., Ltd. 2016
Specifications are subject to change without notice.
Please refer to www.socay.com for current information.
Surge-Arrestor Negative Temperature Coefficient Thermistor
SCNxxD-11 Series
Electrical Characteristics
R25℃
±20%
(Ω)
SCN2.5D-11
SCN3D-11
SCN5D-11
SCN8D-11
SCN10D-11
SCN16D-11
SCN20D-11
SCN22D-11
SCN25D-11
SCN50D-11
2.5
3
5
8
10
16
20
22
25
50
Max
Steady
Current
(A)
5
5
4
3
3
2
2
2
2
1.5
Approx R
Of Max
Current
(Ω)
0.120
0.126
0.288
0.301
0.395
0.488
0.613
0.739
0.838
1.204
Power
Dissipation
Coefficient
(mW/℃)
13
13
13
13
14
14
14
14
14
14
Time
Constant
(s)
46
45
45
45
47
50
52
52
52
52
Part Number
Dimensions (Unit: mm)
Type
A
MAX
C±1
D
MAX
E ± 0.05
F
MAX
Note:
“E”value may be 0.6 for resistors for which the chip's diameter is ≤ 13 and the working current is ≤ 2A.
D-11
12.5
7.5
5
0.8
3
SOCAY Electronics Corp., Ltd.
Revision December 08, 2016
www.socay.com
2/3
@ SOCAY Electronics Corp., Ltd. 2016
Specifications are subject to change without notice.
Please refer to www.socay.com for current information.
Surge-Arrestor Negative Temperature Coefficient Thermistor
SCNxxD-11 Series
Critical Technical Parameters of NTC Thermistor
Rt---Resistance Value at Zero-power
It's a resistance which is got at a fixed temperature on a basis of a testing power which causes resistance to Vary in a range
which can be ignored in relation to the total testing eror.
R
25
---Resistance Value at Rated Zero-power
The design resistance of the thermistor usually refers to the resistance value got at Zero-power at 25
℃
, which is usually
indicated on the thermistor.
B Value
B value stands for the thermal exponent at a negative temperature coefficient. lt's defined as a ratio of the balance between
the natural logarithms of resistance values at zero-power to the balance between the reciprocals of the two temperatures.The
formula is as below:
In this formula: R
T1
is the resistance at Zero-power when the temperature is T
1
,R
T2
is the resistance at Zero-power when the
temperature is T
2
Unless otherwise specified,B value is got by calculating the Zero-power resistances at 25℃ (298.15K) and
50
℃
(323.15K) . It's not a firm constant within the range of working temperature.
Resistance-to-Temperature Coefficient at Zero-power.It refers to the ratio of changes of a thermistor. Resistance value at
Zero-powerwhen The temperature, to the resistance value at Zero-power The formula is as below:
In this formula, "α " stands for the resistance-temperature coefficient at Zero-power when the temperature is T:
R
T
stands for the resistance value at Zero-power when the temperature is T.
T stands for the temperature(in K).
B stands for B value.
Max steady state current.
The maximum allowable continuous current passing through thermistor at 25℃.
Dissipation Coefficient δ
It's the ratio of the changes with a thermistor dissipation power, in a pre-set ambient temperature, to the changes with the
temperature. The formula is as below: δ=
△P/△Tδ
changes in response when the ambient temperature changes, within the
ranges of the working temperature.
Thermal Time Constant
At Zero-power and when amutatio occurs with the temperature,the time "t", which is-spent for finishing 63.2% of the gap
between the beginning temperature and the ending temperature in the thermistor. is directly proportional to"C",the heat capacity
of the thermistor, and is inversely proportional to δ, the dissip ation
constant. That is " τ=C/δ" .
SOCAY Electronics Corp., Ltd.
Revision December 08, 2016
www.socay.com
3/3
@ SOCAY Electronics Corp., Ltd. 2016
Specifications are subject to change without notice.
Please refer to www.socay.com for current information.
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