Capacitors Blog

The capacitor at approximately 75% of the guaranteed maximum capacitance, shall be given a treatment consisting of 5 temperature cycles as follows: Cool the capacitors to -55°C±3°C. Remove the capacitor from the cooling chamber and allow to reach room temp.

Then place in an oven at a temperature equal to maximum operating temperature ±3°C of the respective style.  Remove from oven and allow capacitor to cool to room temperature. The capacitor shall be held at the specified minimum and maximum temperatures long enough to reach equilibrium and in no case less than 15 minutes. The rate of change of temperature in cooling from room temperature, or heating above it shall not be less than 3°C per minute.

The temperature cycles shall be followed by exposures for 96 hours to a relative humidity of 95% at 40°C ±3°C. The capacitor shall then be removed from the humidity chamber and held at 25°C ±5°C with a maximum humidity of 50% for four hours.  The I.R. shall be at least 1 gigaohm, the “Q” at 1 MHz is at least 40% of initial test limit and the capacitance shall not have changed by more than±3% or ±0.5pF, whichever is greater, from its value prior to the start of the temperature cycling.