I’ve been noticing that my PC monitor turns off for a second when I turn the light switches on. My electrician said that this was completely normal due to “Induction”. I’d argue otherwise, like the monitor getting power for a second or two after I turn it off may be due to the induced current in the reverse direction, but this? I suspect a power drip when I turn something on. Like my lights dim down for a second every time I turn my PC on, so it might be the same case for the monitor.

Am I right?

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    \$\begingroup\$ No it's not normal. Which country are you in? Some have higher standards than others. \$\endgroup\$
    – user253751
    Sep 10, 2020 at 13:16
  • \$\begingroup\$ Yea but is induction the reason though? \$\endgroup\$ Sep 10, 2020 at 13:27
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    \$\begingroup\$ Its certainly not normal. Is this the same in every room? Is it the country power grid which is just crap or anything damaged / bad in your home? You should have a professional to measure transfer resistance from your power outlets. there might be a fault in a power outlet, connexion box or the fuse cabinet --> worst case is a cable fire... you should definitely not accept that as normal and install a UPS. Catch the fault and fix it \$\endgroup\$
    – schnedan
    Sep 10, 2020 at 14:45
  • \$\begingroup\$ @user13387446 induction when lights turned on, no. Not in General. lightbulb's have a very low resistance when cold, but get hot in parts of a second. fluorescent lamps are started with huge inductors. So it depends on the lamp type. I worked in a youth hostel which some 60-80 fluorescent lamps switched on at once. Has not caused any issues. so you should never notice a single one \$\endgroup\$
    – schnedan
    Sep 10, 2020 at 14:50
  • \$\begingroup\$ Sounds like poor EMI. What’s your grounding situation? \$\endgroup\$
    – winny
    Sep 10, 2020 at 15:52

1 Answer 1


Sounds like a BrownOut - a dip in the voltage. It may be because your mains voltage is very low compared to what it should be, and the additional momentary load drops it further. If it is a serious problem you need a UPS between the mains and your computer setup


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