An O-ring, also known as a packing or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface. O-rings are one of the most widely utilized sealing products because they’re inexpensive, reliable and have simple mounting requirements. O-rings can be used in a variety of static (non-moving) and dynamic (moving) applications. O-rings are frequently supplemented with a lubricant to assist in installation and sealing asperities.
The ohm is an electrical measurement defined as the resistance between two points of a conductor when a constant potential difference of one volt, applied to these points, produces in the conductor a current of one ampere.
An orifice is any opening, mouth, hole or vent, as in a pipe, tube or a plate used to either regulate or measure the intake or output of a gas or liquid, e.g. "air orifice", or "orifice plate".
An oven rack is a wire constructed shelf that fits inside the cooking compartment of an oven. The wire construction allows for uninterrupted heat and air flow (natural or forced convection). The oven rack is constructed as a weight-bearing unit that wrests on protruding supports inside the oven heating cavity. Oven racks are removable for cleaning and storage when not in use.
Power supplies often have protection from short circuit or overload that could damage the supply or cause a fire. Fuses and circuit breakers are two commonly used mechanisms for overload protection. Overload protection can be automatically enabled in response to high pressure or high temperature situations. Circuit breakers may be manually activated to interrupt the flow of electricity for the purpose of planned equipment maintenance or serviceable repair.