You can also get a voltage meter from the HK equivalent of a Radio Shack. It has a guage that will show you if the voltage is stable and if the needle moves then there is a fluctuation. Has bands so you can tell whether the fluctuation is too much. Also you may be suffering from improper grounding at your place. There are devices to measure/test for that too. Just a light that shows differnt colors. The better surge protectors and conditioners have that built in but you might want to buy the tester instead first as only an electrician can correct improper grounding.