NTC
Thermistor Theory
Please
click on the
section below
to view your
area of interest:
|
|
Specification
of thermistors for applications:
The
preceding sections
have covered topics
relating to the factors
that affect the measured
value of resistance
of a thermistor and
to issues that affect
the correlation between
this measured resistance
value and temperature
of the thermistor.
The next major topics
concern the specification of
thermistors and the
implementation of applications that
use thermistors.
The specification of
thermistors in terms
of part numbers and
product ranges is
dealt with in the product
section. This
section provides
information on the
specification of
Material Curve number,
nominal resistance
value, tolerances,
lead wire options
and associated factors.
All of these attributes
affect the performance
of a thermistor in
an application.
For situations where the specification
of a component part-number are
not clear-cut, BetaTHERM applications
engineering group can provide
advice and customer support.
In
terms of applications,
thermistors represent
a mature product
range and there are
many "standard" application
methods in existence.
However, it can be
difficult to find
information on specific
aspects of thermistor
applications, as
the published literature
on the topic is diverse
and not well catalogued.
The
application notes
that are in the next
sections attempt
to address this situation.
While an in-depth
discussion at text-book
level is beyond the
scope of the catalog,
the application notes
provide a general
overview of methods
of using thermistors
and provide key words
and headings that
may serve as pointers towards
more detailed sources
of information.
The applications section concludes
with some notes on interfacing
thermistors to instrumentation.
This section is also presented
as an overview of some relevant
topics, so that the key-words
and headings can be used to source
more detailed information on
particular items.
Thermistor applications make
use of the basic thermistor features,
such as Resistance versus Temperature
characteristics, zero-power characteristics,
self heating effects and thermal
characteristics like heat capacity
and dissipation constant. It
follows that a knowledge of these
factors is important in understanding
principles of thermistor applications.
Once the general principle of
an applications is understood,
then the concepts of tolerance
and stability and product specification
become relevant in selecting
the actual component to be used
in the application.
 |
|
