Brownouts, or temporary power drops in voltage, are as dangerous to systems as blackouts. Any interruption of voltage to a computer can cause damage or loss of data.
A brownout is a drop in voltage in an electrical power supply system.
Unintentional brownouts can be caused by excessive electricity demand, severe weather events, or a malfunction or error affecting electrical grid control or monitoring systems. Intentional brownouts are used for load reduction in an emergency, or to prevent a total grid power outage due to high demand. The term brownout comes from the dimming of incandescent lighting when voltage reduces.
In some countries, the term brownout refers not to a drop in voltage but to an intentional or unintentional power outage (or blackout).