The positive temperature coefficient of
resistance is very large: approximately 0.7%/°C, making
these units ideal for use in temperature compensating and
sensing applications. Applications include amplifiers,
power supplies, transducers, telemetry, computers, magnetic
amplifiers, thermometry, meteorology, temperature regulation
and over-temperature protection.
Silicon PTC Specifications
Style
Wattage
Rating
@ 100°C
(Watts)
Resistance
Range
(ohms)
Thermal
Time
Constant
(Sec. Max)
Operational
Ambient
Temperature
Range (°C)
Temp. vs.
Coefficient of
Resistance
Table
DS125
0.125
10 to 39,000
34.8
-65 to +150
A
DS200
0.250
10 to 39,000
34.8
-65 to +150
A
DS250
0.250
10 to 39,000
54
-65 to +150
A
DG125
0.125
10 to 10,000
60
-65 to +125
B
DC125
0.125
10 to 10,000
54
-65 to +125
B
DU100
0.125
10 to 10,000
9
-65 to +125
B
RTH22ES
0.250
10 to 10,000
34.8
-65 to +150
A
RTH42ES
0.125
10 to 10,000
60
-65 to +125
B
MlL-Approved Series RTI Electronics' PTC thermistors
are designed and built to withstand all environmental conditions
required by the most stringent Mil specs. They meet or exceed
all requirements of MIL-T-23648 for positive temperature coefficient
thermistors. RTH42ES - Per MIL-T-23648/19.
Glass, hermetically sealed type, similar to DG125 series.
RTH22ES - Per MIL-T-23648/9. Molded style, similar
to DS200 series.
Styles and Dimensions
Temperature vs Coefficient of Resistance
Tables
Table A
TEMP.
°C
Resistance Ranges
@25°C
10
to
75
82
to
160
180
to
620
680
to
1800
2000
to
12,000
15,000
to
39,000
-55
0.615
0.582
0.560
0.550
0.515
0.481
-15
0.790
0.770
0.755
0.740
0.730
0.712
0
0.863
0.847
0.838
0.835
0.825
0.814
25
1.000
1.000
1.000
1.000
1.000
1.000
50
1.160
1.170
1.180
1.200
1.230
1.210
75
1.350
1.370
1.400
1.420
1.450
1.430
100
1.545
1.584
1.623
1.656
1.670
1.670
125
1.750
1.800
1.860
1.920
1.960
N/A
Standard Resistance Values
(Ohms)
10
56
390
2,200
12
68
470
2,700
15
82
500
3,300
18
100
560
3,900
22
120
680
4,700
27
150
820
5,000
33
180
1,000
5,600
39
220
1,200
6,800
47
270
1,500
8,200
50
330
1,800
10,000
Table B
TEMP.
°C
Resistance Ranges @ 25°C (ohms)
10
to
75
82
to
160
180
to
510
560
to
1300
1500
to
6200
6800
to
10,000
-55
0.615
0.582
0.560
0.550
0.515
0.510
-15
0.790
0.770
0.755
0.740
0.730
0.730
0
0.863
0.847
0.838
0.835
0.825
0.825
25
1.000
1.000
1.000
1.000
1.000
1.000
50
1.160
1.170
1.180
1.200
1.230
1.190
75
1.350
1.370
1.400
1.420
1.450
1.400
100
1.545
1.584
1.623
1.656
1.670
1.610
125
1.750
1.800
1.860
1.920
1.960
1.830
Table C
Tolerance at Temperatures
Other Than 25°C
Temp.
(°C)
±5%
(J)*
±10%
(K)*
-55
± 20
± 25
-15
± 13
± 18
0
± 7
± 12
50
± 7
± 12
75
± 9
± 14
100
± 12
± 17
125
± 15
± 20
*Tolerance@25°
The tables above will give the resistance
value ofthe thermistor for the listed temperatures (RT).
To determine the resistance value of the thermistor at temperature
(RT):
Find the temperature in the vertical
column, "Temp. °C". Next find the resistance
range of the thermistor at 25°C, (R25°C), in
the appropriate vertical column. The intersection of the
two columns will give the "coefficient of resistance",
(Rc), of the thermistor at the desired temperature. Compute
as follows:
RT = R25°C x Rc
Resistance tolerances for temperatures
other than 25°C are shown in "Table C". For
instance, the resistance tolerance at +50°C for a Silicon
PTC Thermistor with a tolerance of ± 5% @ 25°C
would be ± 7%.
Recommended Derating Curve
Ordering Information
RTI Electronics' part number
consists of a multi-digit alphanumeric code. The example
shown here:
DG125 122k is the DG125 with resistance
value of 1200 ohms and a tolerance of ±10%
