B59008C0080A040

Symbols and terms
Symbol Term
A Area
C Capacitance
C
th
Heat capacity
f Frequency
I Current
I
max
Maximum current
I
R
Rated current
I
res
Residual current
I
PTC
PTC current
I
r
Residual currrent
I
r,oil
Residual currrent in oil (for level sensors)
I
r,air
Residual currrent in air (for level sensors)
I
RMS
Root-mean-square value of current
I
S
Switching current
I
Smax
Maximum switching current
LCT Lower category temperature
N Number (integer)
N
c
Operating cycles at V
max
, charging of capacitor
N
f
Switching cycles at V
max
, failure mode
P Power
P
25
Maximum power at 25 °C
P
el
Electrical power
P
diss
Dissipation power
R
G
Generator internal resistance
R
min
Minimum resistance
R
R
Rated resistance @ rated temperature T
R
R
R
Tolerance of R
R
R
P
Parallel resistance
R
PTC
PTC resistance
R
ref
Reference resistance
R
S
Series resistance
R
25
Resistance at 25 °C
R
25,match
Resistance matching per reel/ packing unit at 25 °C
R
25
Tolerance of R
25
Sensors
Limit temp. sensors, leaded disks, coated, miniaturized C8
Page 7 of 10Please read Cautions and warnings and
Important notes at the end of this document.
T Temperature
t Time
T
A
Ambient temperature
t
a
Thermal threshold time
T
C
Ferroelectric Curie temperature
t
E
Settling time (for level sensors)
T
R
Rated temperature @ 25 °C or otherwise specified in the data sheet
T
sense
Sensing temperature
T
op
Operating temperature
T
PTC
PTC temperature
t
R
Response time
T
ref
Reference temperature
T
Rmin
Temperature at minimum resistance
t
S
Switching time
T
surf
Surface temperature
UCT Upper category temperature
V or V
el
Voltage (with subscript only for distinction from volume)
V
c(max)
Maximum DC charge voltage of the surge generator
V
F,max
Maximum voltage applied at fault conditions in protection mode
V
RMS
Root-mean-square value of voltage
V
BD
Breakdown voltage
V
ins
Insulation test voltage
V
link,max
Maximum link voltage
V
max
Maximum operating voltage
V
max,dyn
Maximum dynamic (short-time) operating voltage
V
meas
Measuring voltage
V
meas,max
Maximum measuring voltage
V
R
Rated voltage
V
PTC
Voltage drop across a PTC thermistor
α Temperature coefficient
Tolerance, change
δ
th
Dissipation factor
τ
th
Thermal cooling time constant
λ Failure rate
Lead spacing (in mm)
Sensors
Limit temp. sensors, leaded disks, coated, miniaturized C8
Page 8 of 10Please read Cautions and warnings and
Important notes at the end of this document.
The following applies to all products named in this publication:
1. Some parts of this publication contain statements about the suitability of our products for
certain areas of application. These statements are based on our knowledge of typical re-
quirements that are often placed on our products in the areas of application concerned. We
nevertheless expressly point out that such statements cannot be regarded as binding
statements about the suitability of our products for a particular customer application.
As a rule, EPCOS is either unfamiliar with individual customer applications or less familiar
with them than the customers themselves. For these reasons, it is always ultimately incum-
bent on the customer to check and decide whether an EPCOS product with the properties de-
scribed in the product specification is suitable for use in a particular customer application.
2. We also point out that in individual cases, a malfunction of electronic components or
failure before the end of their usual service life cannot be completely ruled out in the
current state of the art, even if they are operated as specified. In customer applications
requiring a very high level of operational safety and especially in customer applications in
which the malfunction or failure of an electronic component could endanger human life or
health (e.g. in accident prevention or lifesaving systems), it must therefore be ensured by
means of suitable design of the customer application or other action taken by the customer
(e.g. installation of protective circuitry or redundancy) that no injury or damage is sustained by
third parties in the event of malfunction or failure of an electronic component.
3. The warnings, cautions and product-specific notes must be observed.
4. In order to satisfy certain technical requirements, some of the products described in this
publication may contain substances subject to restrictions in certain jurisdictions (e.g.
because they are classed as hazardous). Useful information on this will be found in our Ma-
terial Data Sheets on the Internet (www.epcos.com/material). Should you have any more de-
tailed questions, please contact our sales offices.
5. We constantly strive to improve our products. Consequently, the products described in this
publication may change from time to time. The same is true of the corresponding product
specifications. Please check therefore to what extent product descriptions and specifications
contained in this publication are still applicable before or when you place an order. We also
reserve the right to discontinue production and delivery of products. Consequently, we
cannot guarantee that all products named in this publication will always be available. The
aforementioned does not apply in the case of individual agreements deviating from the fore-
going for customer-specific products.
6. Unless otherwise agreed in individual contracts, all orders are subject to the current ver-
sion of the "General Terms of Delivery for Products and Services in the Electrical In-
dustry" published by the German Electrical and Electronics Industry Association
(ZVEI).
Important notes
Page 9 of 10

B59008C0080A040

Mfr. #:
Manufacturer:
EPCOS / TDK
Description:
PTC THERMISTOR, 250R, THT
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union