Reliability indicators mainly include reliability, average service life, failure rate and failure density.
The reliability of the product is the probability of normal operation, which refers to the probability that the product can complete the specified function under the specified conditions and within the specified time. When we are calculating the reliability, the larger the number of products at the beginning of the test and the smaller the test interval, the higher the accuracy of the reliability.
When the product reliability is evaluated, it is also often expressed as failure probability or damage probability. Failure probability is the probability of a corresponding event for reliability. It is very simple and intuitive to assess the reliability of components, switching power supplies, transformers, chargers, or complex systems by the reliability and failure probability of China power adapters. The greater the reliability, the smaller the failure probability and the higher the reliability.
The average service life of a product refers to the average uptime of a product and has different meanings for non-repairable and repairable products.
For non-repairable products, the average service life refers to the average working time before the product fails, usually called MTTF, which is the Mean Time To Failures.
For repairable products, the average service life of a power adapter refers to the average working time between two adjacent failures, that is, the mean time between failures, commonly referred to as MTBF, which is the Mean Time Between Failures.
The meanings of MTTF and MTBF are similar, and their mathematical expressions are also consistent.
The failure rate (failure rate, failure intensity) of a product at any moment is defined as the probability that the product will fail per unit of time after working to moment.
It can also be said that the failure rate is equal to the ratio of the number of failures of the product in one unit of time after moment t to the number of products that are still working at moment.
The failure rate is often used to indicate the reliability index of electronic products and components. The lower the failure rate of the power adapter, the higher the reliability. The unit of failure rate is the percentage of time, such as %/h, %/kh, which means the percentage of failure of the tested product within 1/h (or 1000 hours). In foreign countries, it is commonly used as the unit of failure rate, that is, 1 failed component occurs after 1,000,000 working hours of 1 million components, which is called 1 Fit.
The failure density (failure frequency) of a product refers to the ratio of the number of failed products per unit time to the initial number (total number) of tested products. Products that fail during the test will not be replaced.
The unit of failure density of the power adapter is 1/h, that is, the ratio of the number of failed products per hour to the total number of test products.