Refers to the electrical state in which a switch may rest. Its contacts are held apart or open so that no current flows through its contacts.
The controlled device is open when no signal pressure is applied.
The position of a valve, damper, relay contacts, or switch when external power or pressure is not being applied to the device. Valves and dampers usually are returned to a "normal" position by a spring.
The condition of a circuit or switch that is in a no-fault state. The circuit is open and current is unable to flow. Closing the circuit completes a current path and an alarm condition is initiated.
often referred to as normally passing The state of the output or valve is ON with no external influence.
A term that refers to a switch which is open and disconnected in its normal position.
The state of the output or switch is OFF with no external influence.
(A thermostat switching action.) A fan type application; contacts close on temperature rise at a pre–determined temperature to energize the circuit. Contacts automatically re–open as the device cools to pre–determined temperature. /\ OEM: Original equipment manufacturer. A company that includes hardware components from other companies in its own product.
A switch, relay, valve or damper that is open when the power is not being applied.
In electronics, a normally open switch is one that normally prevents current flow and which allows current to flow when it is perturbed. Such a switch requires a constant intervention in order to keep it closed. A non-electronic example of this would be the safety on a lawnmower, which will prevent gas flow to the engine when it is let go.