blackout

blackout

1. a momentary loss of consciousness, vision, or memory

2. a temporary electrical power failure or cut

3. Electronics a temporary loss of sensitivity in a valve following a short strong pulse

4. a temporary loss of radio communications between a spacecraft and earth, esp on re-entry into the earth's atmosphere

blackout

[′blak‚au̇t]

(communications)

radio blackout

(electricity)

The shutting off of power in an electrical power transmission system, either deliberately or through failure of the system.

blackout

The relationship between acceleration and time at maximum G required to produce symptoms of grayout and blackout.

i. A condition of temporary loss of vision, possibly also loss of consciousness, resulting from the effect of high and sustained positive acceleration (g) on the body. A condition that occurs at g value higher than 1 that causes gray-out. Normally, this occurs when the body is exposed to +4 and +4.5 g for about 10 seconds or more. This can be postponed slightly by using a g-suit, by crouching, or by using a reclining seat. The onset of gray-out and blackout conditions varies from individual to individual. It is also dependent on physical conditioning.
ii. The fadeout of radio communications caused by changes in the ionosphere resulting from a nuclear explosion or ionospheric disturbances.
iii. An enforced period during which all lights in an area are turned off or concealed, so as not to be visible from the air. It is one of the passive air defense measures.

blackout

A complete loss of power. See brownout.