Voltage drop
A voltage drop may refer to any of the following:
1. Alternatively called a brownout, dip, sag, voltage reduction, and voltage sag, power fluctuation, a voltage drop is any decrease in voltage under one second. Longer reduction in voltage is called undervoltage.
Power line sags often occur during the summer and when too much equipment is plugged into the same circuit. When a voltage drop occurs, your computer can lock up, lose data, crash, and may experience hardware failure, such as the hard drive failing.
If your area experience brownouts, we recommend purchasing an SPS (standby power supply) or UPS (uninterruptible power supply) for your computer and other devices and equipment to help prevent any damage and corruption.
2. Linux command, see the Linux sag command page for further information about this term.