Drift is a time-related effect in which parameters such as frequency or voltage
change continuously from their nominal value. Depending on which physical parameter changes, one speaks of frequency drift or voltage drift. The change may be due to the influence of ambient temperature, aging or stress on electronic components. The drift refers to the change of the physical quantity in a specified period of time, e.g. x millivolts per second. It can occur in both directions and does not have to be linear. I.e. the drift can be faster for new components than for aged ones.