HAST (Highly Accelerated Stress Test) is a type of test that is used to evaluate the reliability of electronic components and other materials under high temperatures and humidity. A HAST test chamber is a device that provides controlled conditions of high temperature and humidity to simulate the effects of aging and degradation on materials over a shorter period of time than would occur in normal use.

During testing, the sample to be evaluated is placed in the HAST chamber, which is then heated to a high temperature and subjected to a high-pressure steam environment. The temperature and humidity levels are carefully controlled to ensure that the sample is subjected to the appropriate conditions.

The purpose of the HAST test is to identify any weaknesses or defects in the material that may cause it to fail prematurely in real-world use. By exposing the sample to accelerated aging conditions, engineers can evaluate the long-term reliability of the material and make any necessary improvements to its design.

HAST test chambers are commonly used in the development and testing of electronic components, such as integrated circuits, printed circuit boards, and semiconductor devices. They are also used in other industries where materials must be able to withstand harsh environmental conditions, such as the aerospace, automotive, and medical device industries.