The on-off click is one of the smallest sounds in foley and one of the most overlooked — the difference between a real mechanical switch and a software-generated tap is the slight irregularity of physical contact, and that's exactly what an app prototype needs to feel finished. These 20 on off sounds work that physical register: a wall light-switch flick captured at conversation distance, the tactile button-press of a TV remote, the soft pop of a CRT television actually turning off, and the deeper thunk of a server PSU being killed at the back. A bench of subtle electronics-power-up cues supports app-confirm work.
UI designers and app developers pull the tactile clicks for toggles and switch confirmations — the slight irregularity is what makes a digital interface feel grounded. Video editors reach for the TV turn-off pop as a transition out of a montage. For sci-fi work, the server-thunk pitched down by a few semitones reads as a much bigger system going dark. Ringtone and notification creators use the subtle power-up cues for notification chimes. Free to download for apps and videos with no signup or licence chase.