In an ideal world, your wall socket would provide an infinite stream of perfect power, at constant voltage and cycling exactly the same number of time per second. Don’t count on it.
- Power failure. When a superhero loses his ability to fly or a total loss of utility power.
- Power sag. Post-lunch sleepiness or short-term low voltage.
- Power surge (spike). Rush of energy following a double shot of espresso or short-term high voltage more than 110 percent of normal.
- Under-voltage (brownout). When your amp’s too wimpy to handle the bass line or reduced line voltage for an extended period of a few minutes to a few days. Often happens during the summer months when everyone is cranking up their air conditioners.
- Over-voltage. Inhuman cheerfulness exuded by aerobics instructors or increased line voltage for an extended period of a few minutes to a few days.
- Electrical line noise. Excuse you use to get off the phone quickly or a high power frequency power wave caused by radio frequency interference (RFI) or electromagnetic interference (EMI).
- Frequency variation. Fluctuation in how often you do laundry from week to week or a loss of stability in the power supply’s normal frequency of 50 or 60 Hz.
- Switching transient. Breaking up with your significant other only to get back together every six months or instantaneous under-voltage in the range of nanoseconds.
- Harmonic distortion. “Music” blaring from your nephew’s headphones or the distortion of the normal power wave, generally transmitted by unequal loads.