NTC THERMISTORS:
TYPE P20/25/30
MINIATURE THERMOPROBES
DESCRIPTION:
The Type P20, P25 and P30 miniature THERMOPROBES
consist of a small bead thermistor hermetically sealed in
the tip of a shock resistant solid glass rod. The miniature
THERMOPROBES have improved stability over glass coated
and ruggedized glass bead thermistors.
APPLICATIONS:
The Type P20, P25 and P30 miniature bead-in-glass
probes feature high reliability, ease of handling and very fast
response time. The longer body length
makes them particularly well suited for applications where
both fast response and immersion in fluids are the
major requirements.
DATA:
All THERMOPROBES are aged for extended periods of time.
As such, they exhibit excellent stability for all service temper-
atures at or below the aging temperature. THERMOPROBES
which are manufactured with Material System “E” are aged
at 105°C; those manufactured with a Material System having
a 25°C/125°C ratio of 16.9 or less are aged at 200°C; and
all other Material Systems are aged at 300°C. Intermittent
operation at temperatures up to 600°C is permissible,
however, degraded stability will result when the aging
temperature is exceeded.
DIMENSIONS:
platinum alloy lead-wires
CODING:
The code number to be ordered may be specified as follows:
P
20
AA
A
103
N
Tolerance code letter (see NOTE 1 and TABLE B)
Zero-power resistance as 25°C (see NOTE 2)
Material System Code Letter (see TABLE A)
Probe length code letter “AA” = .063" ± .015"
“A” = .125" ± .032"
“B” = .250" ± .050"
Maximum Probe Diameter in mils. (Specify 20, 25 or 30.
Style “P” denotes miniature bead-in-glass THERMOPROBE structure.
NOTE 1:
Special tolerances are available on request. Consult factory for special resistance tolerances, non-standard
resistances and/or non-standard temperatures.
NOTE 2:
The zero-power resistance at 25°C, expressed in Ohms, is identified by a three digit code number. The first two digits
represent significant figures, and the last digit specifies the number of zeros to follow. Example: 10k Ohms = “103”.
The standard resistance values are from the 24-Value series decade as specified in Military Standard MS90178.
1.0 / 1.1 / 1.2 / 1.3 / 1.5 / 1.6 / 1.8 / 2.0 / 2.2 / 2.4 / 2.7 / 3.0
3.3 / 3.6 / 3.9 / 4.3 / 4.7 / 5.1 / 5.6 / 6.2 / 6.8 / 7.5 / 8.2 / 9.1
BOWTHORPE THERMOMETRICS
Crown Industrial Estate, Priorswood Road
Taunton, Somerset TA2 8QY UK
Tel +44 (0) 1823 335200
Fax +44 (0) 1823 332637
THERMOMETRICS, INC.
808 US Highway 1
Edison, New Jersey 08817-4695 USA
Tel +1 (732) 287 2870
Fax +1 (732) 287 8847
KEYSTONE THERMOMETRICS CORPORATION
967 Windfall Road
St. Marys, Pennsylvania 15857-3397 USA
Tel +1 (814) 834 9140
Fax +1 (814) 781 7969
TABLE A: THERMAL AND ELECTRICAL PROPERTIES:
The following table lists the THERMAL and ELECTRICAL properties for all Miniature bead-in-glass THERMOPROBES.
All definitions and test methods are per MIL-PRF-23648.
THERMISTOR TYPE:
BODY DIMENSIONS:
Max. Diameter:
Standard
Body
Lengths
lead-wires:
Nom. Diameter:
Minimum Lead Length:
Lead Material:
**
(.002"
P20
.020"
(.51 mm)
.025"
.125"
.250"
.002"
P25
(.64 mm)
—
(3.2 mm)
(6.3 mm)
(.05 mm)
.030"
.125"
.250"
.003"
P30
(.76 mm)
—
(3.2 mm)
(6.3 mm)
(.08 mm)
“L”
{
code
code
code
“AA”
“A”
“B”
.063"
(1.6 mm)
.125"
(3.2 mm)
.250" (6.3 mm)
**
(.03 mm)
required)
.250"
(6.3 mm)
Platinum Alloy
.0011"
.250"
(6.3 mm)
Platinum Alloy
.250"
(6.3 mm)
Platinum Alloy
MATERIAL SYSTEM:
CODE
LETTER
E
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
D
D
THERMAL TIME CONSTANT:
Still Air at 25°C:
Plunge into Water:
DISSIPATION CONSTANT:
Still Air at 25°C:
Still Water at 25°C:
POWER RATING: (in air)
Maximum Power Rating:
100% Max. Power to:
Derated to 0% at:
R-vs-T
CURVE
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0
25/125
RATIO
5.0
11.8
12.5
14.0
16.9
19.8
22.1
22.7
29.4
30.8
32.3
35.7
38.1
45.0
48.1
56.5
75.6
81.0
Nominal
Resistance
Range @ 25°C
—
–
–
–
–
–
–
27kΩ –
75kΩ –
130kΩ –
240kΩ –
360kΩ –
820kΩ –
1.3MΩ –
3.3MΩ –
6.8MΩ –
—
—
300Ω
680Ω
1.6kΩ
3.6kΩ
6.8kΩ
Nominal
Resistance
Range @ 25°C
—
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
—
—
Nominal
Resistance
Range @ 25°C
—
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
—
680Ω
1.6kΩ
3.6kΩ
6.8kΩ
27kΩ
75kΩ
130kΩ
240kΩ
360kΩ
820kΩ
1.3MΩ
3.3MΩ
6.8MΩ
10MΩ
300Ω
680Ω
1.6kΩ
3.6kΩ
6.8kΩ
27kΩ
75kΩ
130kΩ
240kΩ
360kΩ
820kΩ
1.3MΩ
3.3MΩ
6.8MΩ
680Ω
1.6kΩ
3.6kΩ
6.8kΩ
27kΩ
75kΩ
130kΩ
240kΩ
360kΩ
820kΩ
1.3MΩ
3.3MΩ
6.8MΩ
10MΩ
100Ω
300Ω
750Ω
1.5kΩ
3.0kΩ
6.8kΩ
13kΩ
18kΩ
51kΩ
82kΩ
150kΩ
330kΩ
680kΩ
1.5MΩ
3.0MΩ
6.2MΩ
300Ω
750Ω
1.5kΩ
3.0kΩ
6.8kΩ
13kΩ
18kΩ
51kΩ
82kΩ
150kΩ
330kΩ
680kΩ
1.5MΩ
3.0MΩ
6.2MΩ
10MΩ
1.6 sec
18 msec
2.0 sec
23 msec
3.0 sec
60 msec
.14 mW/°C
.70 mW/°C
.16 mW/°C
.80 mW/°C
.30 mW/°C
1.50 mW/°C
.020 Watts
150°C
300°C
.025 Watts
150°C
300°C
.035 Watts
150°C
300°C
RESISTANCE -VS- TEMPERATURE CHARACTERISTICS: The nominal resistance range for the zero-power resistance at 25°C is shown
for each miniature bead-in-glass THERMOPROBE Type and each available Material System. Each Material System is denoted by
an ordering Code Letter, a referenced Curve number and the nominal 25°C/125°C resistance ratio.
TABLE B: STANDARD TOLERANCES:
Tolerance Code Letter
± % Tolerance at 25°C
F
1
G
2
J
5
K
10
L
15
M
20
N
25
P
30
Q
40
R
50
S
Non-standard – consult factory
BOWTHORPE THERMOMETRICS
Crown Industrial Estate, Priorswood Road
Taunton, Somerset TA2 8QY UK
Tel +44 (0) 1823 335200
Fax +44 (0) 1823 332637
THERMOMETRICS, INC.
808 US Highway 1
Edison, New Jersey 08817-4695 USA
Tel +1 (732) 287 2870
Fax +1 (732) 287 8847
KEYSTONE THERMOMETRICS CORPORATION
967 Windfall Road
St. Marys, Pennsylvania 15857-3397 USA
Tel +1 (814) 834 9140
Fax +1 (814) 781 7969
242B
