Find more information about:

• High Temperature Mica Paper Capacitors
• High Temperature Mica Paper Capacitor Performance Specifications
• High Temp PTFE Capacitors
• PTFE Film/Foil Capacitors Performance Specifications

High Temperature Mica Paper Capacitors

Custom's made-to-order mica paper capacitors are available for a variety of high temperature / high voltage applications. These types of capacitors can be rated up to 260°C for a variety of applications that include, but are not limited to, down-hole oil and gas exploration and drilling, jet engine ignition systems, etc. This type of high reliability capacitor can be packaged with a variety of materials to meet your high temperature / high voltage requirements. Our mica paper capacitors can be designed to meet most stringent electrical, environmental, and physical requirements. To order your high temperature / high voltage mica paper capacitors, please contact our sales department or visit our directory for a complete listing of our International Sales Representatives.

Configurations available:

• Single-section Capacitors
• Multi-section Capacitors
• Multi-capacitor Assemblies

A variety of high temp mica paper capacitor styles are available using a combination of materials. The following table lists these materials and their associated maximum temperatures.

Terminations available:

• Solid Wire Lead
• Insulated Wire Lead
• Turret Terminal
• Threaded Studs or Inserts
• PTFE Insulated Wire Lead
• PTFE, Ceramic, or Glass Insulated Terminals

Mounting available:

• Threaded Studs or Inserts
• Plates or Brackets

High voltage applications up to 15 kVdc or 1000 Vrms.

Units are available in rectangular or tubular designs. Metal housings are available in aluminum, stainless steel or plated brass.

Meets shock and vibration requirements in drill bit applications. Meets requirements in AC or DC motor applications.

Back to Top

High Temperature Mica Paper Capacitor Performance Specifications

Capacitance Range:
100 pF to several µF
Capacitance Tolerance:
Standard is ± 10 %. Tighter tolerances available.
Voltage Range:
1 to 15 kVdc
Dissipation Factor:
0.5 % Max at 25°C, 2.0 % Max at 200°C
Insulation Resistance:
5,000 Megohm·µF Min at 25°C,
5 Megohm·µF Min at 200°C
Temperature Coefficient of Capacitance:
+ 8 % Max from 25°C to 200°C
- 4 % Max from 25°C to -65°C
Dielectric Withstanding Voltage (DWV):
Typically 110 % to 200 % of rated voltage for 15 to 60 seconds.
Environmental per MIL-STD-202:
Vibration per Method 201 and 204
Shock per Method 213
Thermal Shock per Method 107, Test Condition B
Humidity per Method 103, Test Condition B
Moisture Resistance per Method 106, Steps 1 through (Metal or Polyimide Housings Only) Immersion per Method 104,
Test Condition B (Metal or polyimide Housings Only)

Back to Top

High Temp PTFE Capacitors

Two types of construction are available:

• Film/Foil

The dielectric material used in the design and construction of PTFE film capacitors is tetrafluoroethylene (TFE) film. This type of film can be manufactured with several basic processes: casting, extrusion, or skiving (i.e., shaved continuously from the surface of a cylindrical block of molded resin). Casting is the preferred process for the thin, multilaminar TFE film that is used in Custom's lower voltage high temperature capacitor products. The casting process includes deposition of extremely small particles of TFE (i.e., an average diameter of approximately 0.2 µm) from an aqueous suspension to form a continuous thin film on a belt, heating and sintering, and fusing (at temperatures > 370°C). The casting process provides uniform tensile strength and elongation in linear and transverse directions and a smooth surface profile.

Back to Top

PTFE Film/Foil Capacitors Performance Specifications

Capacitance Range:
Contact us for a detailed table
Voltage Ratings:
100, 200, 400, 600 Vdc
Dissipation Factor:
0.02 % Max, over temperature range
Insulation Resistance (RT):
50 VDC Rating: 1 x 10¹¹ ohm·µF, but need not to exceed 10¹¹ ohms
All other ratings: 1 x 10¹² ohm·µF, but need not to exceed 10¹² ohms
Insulation Resistance (200°C):
All ratings: 1 x 10⁹ ohm·µF, but need not to exceed 10⁹ ohms
Temperature Coefficient of Capacitance:
+ 1 % to - 3 %, from 25°C to 200°C
Dielectric Withstanding Voltage (DWV):
Typically 150 % of rated voltage

Recommended for high frequency applications.

Back to Top

Note: Mylar is registered trademark of the E.I. Dupont Corporation