A plain circle (◯) — IEC 60417-5008, marking the control position that disconnects power from the equipment.
Also known as: Power off symbol, IEC 60417-5008, Circle symbol on a switch
The circle of the classic |/O switch pair. IEC 60417-5008 indicates that using the control will disconnect power to the device — a genuine disconnection, unlike the standby symbol.
Indicates that using the control will disconnect power to the device. Conventionally paired with the vertical bar (power on), echoing binary 0 and 1.
Contexts: Electrical equipment
A single plain circle with nothing inside it, like the digit zero.
A plain circle means power is genuinely disconnected; the standby symbol's circle-with-a-line does not disconnect power at all.
The two halves of the conventional |/O switch marking: the circle means off, the bar means on.