Meaning of 電気用 in Japanese

このエアコンは電気を多量に消費する。
This air conditioner consumes a lot of electricity.

電気を消すのを忘れないで。
Don't forget to turn the light off.

何の用でここに来たのですか。
What has brought you here?

それから服を着て、講義用のメモを手さげ鞄に詰め込み、階段を駆け下りた。
Then he got dressed, stuffed his lecture notes into his briefcase, and ran down the stairs.