Failure Rate

Failure rate is often measured as mean-time-between-failure. A failure can be one that can be recovered, or one that is permanent. Note that in this context, failure is conditional to the fact that ``components are operated in an environment that is well within the acceptable operating parameters.'' In other words, we are not subjecting components to extreme heat and other harmful environments.

Most electronic components either work, or they have some kind of manufacturing defects that cause the component to fail. Most manufacturers have in-house test procedures that ensure the functionality of components before such components are shipped.

Sometimes, it is necessary to operate a component outside the ``safe parameters''. For example, an IrED may be rated for 20mA of continuous forward current. The same IrED can probably be pulsed at 50 $\mu \mathrm{s}$ using a 50ms pulse period using a 1A pulse current. However, most IrED manufacturers do not test IrEDs using the 1A pulse current method. As a result, IrEDs that pass the manufacturer's test (20mA continuous) may not work when pulsed with 1A, even at a low duty cycle.

If you are operating a component outside the ``safe parameters'', you may need to perform your own tests. For example, you may find that only 75% of all IrEDs can survive the pulsed current test. How you design your own ``burn in'' test depends on the type of component as well as how you plan to use it.