If we are lucky ESD or overvoltage/overcurrent will destroy components instantly - so it is clear that there is a problem. More commonly, though, such stress may cause damage, which results in premature death long after the stress which initiated the failure has gone. Diagnosing the cause of such failure is very difficult and may be impossible.
When designing any circuit it is well to consider the lifetimes and failure mechanisms of the components used, and whether there are any potential problems and possible sources of stress damage to the components under the most extreme of the allowable conditions of use. Any such problems should be considered, and where possible minimized, in the final design.
1 See the Vishay Application Note:- "Predictable Components: Stability of Thin Film Resistors "
2 Some useful papers from the Emerson Corp are:- SL-24617 The Effect of Regular, Skilled Preventive Maintenance and Remote Monitoring on Critical Power System Reliability / SL-24628 Longevity of Key Components / SL-24630 Replacing-Capacitors.
3 See Electromigration.
4 For low power supplies a suitable resistor is unlikely to dissipate significant power (for instance a 33 Ω resistor in a 5 W/110 V supply will keep the surge below 5 A and will dissipate <70 mW) but with larger supplies of this type a thermistor may be necessary.
James Bryant was an applications manager at Analog Devices from 1982 until his retirement in 2009 and still writes and consults for the company.
This article first appeared on EE Times' Planet Analog website.