- Value Change Over Temperature-
[Dielectric]
[Temperature] [Board
Placement]
[IC
By-Pass Caps] [equivalent Cap
Circuit]
[Capacitor
Decoupling Value] [Terms]
[Surface Mount Chip Size] [MIL Specs]
[Capacitor
Manufacturers]
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There are a number of reasons a capacitors value will change.
This particular graph shows value change over temperature for various dielectrics.
The graph above shows the change in Capacitance value vs Temperature
change for a number of different plastic film capacitor dielectric
types. This is not the same as the tolerance listed on the capacitor. The
tolerance value marked on the device indicates what the expected value
should be at room temperature. Derating guide lines for capacitors is
listed on the Component De-Rating
page.
The graph shows how a capacitor's value will change over a change in temperature, regardless of the tolerance.
One way to compensate for a temperature change is to use two capacitors in parallel;
one capacitor having a positive change and one having a negative change, so they cancel each other out [if you have the space for two caps].
Paper Dielectric [Paper Capacitors Manufacturers]
Capacitors that use paper dielectric are used in High voltage applications. Paper devices should not be used in a high moisture
environment unless the device is in a hermetic case, the capacitance will increase, the power factor, insulation resistance, dielectric strength, and Capacitor life will degrade. Paper capacitors have a near 10% tolerance.
Plastic FILM [Plastic Film Capacitors Manufacturers]
Mylar: has a wide temperature change of 20% over -55 to +125C. Moisture absorption is half that of paper. Mylar is the same as polyester. The term Mylar is a trade name.
Polycarbonate: Out performs Mylar in all areas. Low Power
factor, works best with AC. Polycarbonate has a low temperature
drift (graph below), dissipation factor, and dielectric absorption.
Use polyphenylene sulfide as a possible replacement.
Polyester: Replaces paper for many applications, and smaller
in size. Polyester does not have the moisture problem that paper
does, but does have a worse tolerance, at 20% ~ over -55 to +125C.
May also be called PETE, or PETP. The Polyester Dielectric has an
Absorption of around 0.20%.
Polypropylene: It has negative temperature coefficient.
Polysulfone: Has a very high operating temperature of +170C.
Polystyrene: Will only work to +65C. It has a flat to
negative temperature coefficient.
Polyetrafluoroethylene (PTFE): [Teflon] Has a very high operating temperature of +170C.
MICA High Precession. The material is inert it will not change over time or temperature. Mica Capacitor
CERAMIC [Ceramic Capacitors Manufacturers]
The standard By-pass capacitor resides with in two main classes, Type I
and II; However the major distinction resides with the temperature and
frequency characteristics. Normally the frequency characteristics come
first and then the temperature {It depends on the design application}.
NPO (Type I) Stable over temperature [CGO] EIA temperature
Coefficient Designation]
X7R (Type II) 15% variation over temperature
Z5U General Purpose [EIA temperature characteristic code]
Y5V General Purpose [EIA temperature characteristic code]
X | -55oC | 2 | +45oC | A | +/- 1% |
Y | -30oC | 4 | +65oC | B | +/- 1.5% |
Z | +10oC | 5 | +85oC | C | +/- 2.2% |
- | - | 6 | +105oC | D | +/- 3.3% |
- | - | 7 | +125oC | E | +/- 4.7% |
- | - | - | - | F | +/- 7.5% |
- | - | - | - | P | +/- 10% |
- | - | - | - | R | +/- 15% |
- | - | - | - | S | +/- 22% |
- | - | - | - | T | - 33%, + 22% |
- | - | - | - | U | - 56%, + 22% |
- | - | - | - | V | - 82%, + 22% |
Related Issues:
Capacitor Failure Rates over Temperature
Capacitor Case Size vs. Altitude
Engineering tags: Capacitor value change over Temperature. Maximum Operational Range of a Dielectric.
What is the change of capacitance over temperature for Plastic Film Dielectric.
What are the different types of capacitor Dielectric material. What are
the different EIA codes for Temperature Characteristics.
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