I understand that dirty electricity can reduce the lifespan of computers overall even through they are now designed to work over a range of voltages; usually 90v to 130v instead of an absolutely pure sinewave at 120v. I am not talking about brown out or surge conditions but regular every day noise on an AC line.

From what I've gathered harmonic or other signal irregularities in the power input can cause the device to draw more than it would need otherwise causing additional heat to be generated.

But it is also well known that the AC to DC conversion process can have residual AC signal left over, which is generally tolerated by most systems but unwanted in audio work or critical hardware such as ICU units, air traffic control, etc to avoid any possible catastrophic event.

In those fields they use isolation transformers, power conditioners, and voltage regulators to ensure that the power is a pure sinewave at a constant 120v (as Tesla intended).

Lately I have been wondering if modern computers are be susceptible to that residual powerline noise, and if it could cause any soft errors that would normally go unnoticed soft errors on say, a control bus, signal lane, whatever.

Cosmic rays do this all the time much to the dismay of astronomers around the world, but what about bad quality electricity?


Switching power supplies filter out noise from the AC side quite well.

The first capacitor stage after the rectifier is a fairly good band stop -- it will pass DC, but smooth out the AC frequency, so the lower transition band is in the tens of Hz. It will pass higher frequencies, because the bulk capacitance is rather large, and so is the inductance of the capacitors.

This passes through to the chopper and transformer stages, after which another filter suppresses the chopper frequency and its harmonics, which is where the majority of noise from AC will be -- higher frequencies that would pass this filter don't transmit well through the mains network.

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