der Blackout
blackout
A sudden and widespread failure of the power supply.
Wegen des Sturms gab es in der ganzen Stadt einen Blackout.
Because of the storm, there was a blackout across the whole city.

blackout
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blackout
A sudden and widespread failure of the power supply.
Wegen des Sturms gab es in der ganzen Stadt einen Blackout.
Because of the storm, there was a blackout across the whole city.

'Blackout' is a word from English. In German, it is usually combined with the verb 'haben' (to have) or the phrase 'es gibt' (there is / there are) to describe the occurrence of the event.
Ich hatte bei der Präsentation einen totalen Blackout.
I had a total blackout during the presentation.
You can recognize the meaning from the context. If it is about electricity, technology, or a city, it means a power outage. If it is about a person in a stressful situation such as an exam, it means a loss of memory.
Die ganze Stadt war vom Blackout betroffen.
The whole city was affected by the blackout.
To describe the severity of a blackout, the adjectives 'komplett' (complete), 'total' (total), or 'kurz' (brief) are often used. For a power outage, 'großflächig' (widespread) also fits.
Er hatte nur einen kurzen Blackout und konnte dann weitersprechen.
He had only a brief blackout and was then able to continue speaking.
fainting / powerlessness
'die Ohnmacht' and 'der Blackout' can both mean that someone is briefly not fully conscious. 'Ohnmacht' is used especially when a person really becomes unconscious, for example because of circulatory problems or shock. 'Blackout' can also mean a brief loss of memory, such as in an exam when you suddenly cannot remember anything. In addition, 'Blackout' can mean a power outage. Learners confuse the words because both describe a sudden failure. If someone collapses or passes out, 'Ohnmacht' fits better; if someone suddenly cannot remember anything, 'Blackout' is more natural.

In der Prüfung hatte Max plötzlich einen Blackout und konnte die einfache Frage nicht beantworten.
During the exam, Max suddenly had a blackout and could not answer the simple question.
Nach dem langen Stehen fiel die Frau kurz in Ohnmacht.
After standing for a long time, the woman briefly fainted.