What are the effects on film capacitors when the operating temperature is too high or too low

Film capacitors are most afraid of high-temperature and high-humidity working environments. This is especially true in power supplies, where improper design often places electronic components with high heat generation too close to film capacitors, making the film capacitors extremely easy to damage. What are the effects of excessively high or excessively low operating temperatures on film capacitors?

1. What is the operating temperature range of film capacitors?

There are many types of film capacitors, and their temperature resistance ranges vary to some extent.

Powder-coated film capacitors: that is, film capacitors sealed with epoxy resin on the outside. Their temperature resistance is generally as follows:

CBB capacitors: high-quality ones are -40°C to 105°C, and low-quality ones are -40°C to 85°C.

CL capacitors: high-quality ones are -40°C to 120°C, and low-quality ones are -40°C to 85°C.

Box-type CBB capacitors: -40°C to 110°C.

The above are the operating temperatures of some of the most common film capacitors. Generally, when purchasing capacitors, the specification sheet will indicate the operating temperature range of the film capacitor.

2. What happens if the temperature of a film capacitor is too low?

Film capacitors can operate in environments as low as -40°C. Under normal conditions, it is difficult to encounter such a low operating environment, so it can be understood that film capacitors do not need to worry about the effects of excessively low temperatures.

3. What happens if the temperature of a film capacitor is too high?

As long as the purchased film capacitor has no quality problems, damage to film capacitors is generally caused by excessively high temperatures. For example, if there are electronic components with high heat generation near the film capacitor, or if the entire circuit generates a large amount of heat and has poor heat dissipation, or if the equipment operates under direct sunlight and in high-temperature and high-humidity environments, all of these can easily cause the film capacitor temperature to become too high and damage it.

If a film capacitor operates for a long time at a temperature above its allowable range, the thermal aging of the film capacitor will be accelerated. The service life of the film capacitor will be significantly reduced. Generally, the higher the temperature, the shorter the service life of the film capacitor; when the temperature is particularly high, the service life of the film capacitor will decrease sharply.