Electronic Component Failure

It's easy to blame 'bad' power for damaging electronic components but to substantiate this we need to investigate the means by which this happens.

Apart from the usual "wearing out", which is as a result of impurities within the material which make up the active portions, electronic components are also weakened and damaged when subjected to currents beyond their carrying capacity. This damage usually results from the power dissipated (as heat) within the component material owing to the natural voltage drop through the material while a current is flowing through it.

This damage is related to the energy the material needs to dissipate and is therefore related to current vs time. If a component can handle 1A for 1 second, it is not uncommon to find it can handle 10A for 0.1S, although there is a maximum the material will conduct regardless of the time.

Apart from fuses (which are designed to go open circuit should the current exceed a specified maximum), most electronic components "fuse" (melt together) and become an almost dead short when subjected to damaging currents. An electronic "domino effect" can ensue should the damaging current be sustained for long enough and be passed from one component to the next.

But the story does not just end with a catastrophic failure. Sometimes the failures are so small that their effect is not immediately seen, almost the electronic equivalent of "chipping away at it until it breaks". When viewing power quality complaints with a view to establishing whether a bit of dirty power is responsible or not, don't just view it as " it was not big enough to cause damage". Also look at what happens when a component is subjected to many smaller blows.

Please note that we are not claiming the reasons given in the following sections are the only reasons components fail, but rather as pointers to probable causes. In many cases it is simply that the equipment is under-designed (economics!) with components "living on the edge".

What we also need to bear in mind is the "human factor", a prime example is resetting a PC with the on/off switch. We start our tour by meeting the very device that is meant to protect against high in-rush currents is often circumvented by an ill-informed human - usually a badly trained IT individual....

But we start with the first human in the chain... the guy who made the gear!

Our tour in understanding component is:
  Lack Of Suitable Filtering
  Unsuitable In-rush Protection
  Persistent Fuse Blowing
  Input Rectifier Diodes
  Between Rectifiers and PSU Output
  Damage Through Latch-up
  Component Failure after the PSU

Lack Of Suitable Filtering  >>

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© 05.10.01