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Our most basic capacitors are Unencapsulated, that is, a bare impregnated mica paper section with packaging. Used where space or weight is a consideration, they can be manufactured to meet your most stringent electrical, environmental, and physical requirements. Unencapsulated capacitors require protection from humid environments and are generally used in assemblies where subsequent potting or encapsulation is applied, especially in high-altitude applications. Custom's Unecapsulated capacitors can be constructed with solder pad, wire lead, or tab lead terminations. They have an operating temperature range of -65° to 125°C and are available in the following configurations:

  • Single-Section Capacitors

  • Multi-Section Capacitors

  • Multi-Capacitor Assemblies

Basic Capacitor (Unencapsulated, Wrap and Fill) Performance Specifications

Capacitance Range:

  • 100 pF to several µF Capacitance


  • Standard is ± 10 %. Tighter tolerances are available

Voltage Range:

  • 1 to 50 kVdc

Dissipation Factor:

  • 0.5 % Max at 25°C

  • 1 % Max at 125°C

Insulation Resistance:

  • 5,000 Megohm•µF Min at 25°C

  • 25 Megohm•µF Min at 125°C

Temperature Coefficient of Capacitance:

  • + 5 % Max from 25°C to 125°C

  • - 3% 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 (Wrap and Fill Only)

  • Humidity per Method 103

  • Test Condition B (Wrap and Fill Only)

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

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