About glass capacitors
Glass dielectric capacitors use thin, high-purity glass as the dielectric in a fused monolithic construction. They were developed as a high-reliability alternative to mica and became the standard for applications where failure or drift cannot be tolerated.
Key characteristics
- Extremely stable performance across wide temperature ranges (typically −75 °C to +200 °C)
- Zero aging rate — capacitance does not drift over time or years of storage/use
- Radiation hard and resistant to shock, vibration, moisture, and vacuum
- Hermetic glass-to-metal seals
- Low dielectric absorption and high Q
Typical applications
- Space and satellite systems
- Aerospace, missiles, and avionics
- Downhole oil & gas instrumentation
- Military and high-reliability legacy equipment
- Any circuit requiring long-term parameter stability in harsh conditions
Availability
Most glass capacitor series were discontinued roughly 15–20 years ago. Remaining stock is used primarily for repair, sustainment, and continued support of systems originally designed around these parts. Because they do not degrade with age, properly stored units remain fully usable decades after manufacture.