Bayonet base
From Wikipedia, the free encyclopedia
A Bayonet base is a style of Light Bulb base with small lugs to retain it in the socket.
To remove the bulb the user presses the bulb down against a spring in the socket and turns the bulb a fraction of a turn. The lugs that retain the bulb can then slide through slots in the socket and the bulb can be removed.
Bayonet Bulbs are often used in applications such as Automotive lighting where vibration may loosen conventional bulbs. The bulb may have slightly offset lugs to ensure it is only inserted in one direction, this is particularly true in Bulbs like the 1157 automobile taillight which has two different filaments to act as both a running light and a signal light.
Bayonet base or cap is often abbreviated to BC often with a number after. The number refers to the diameter of the base e.g. BC22 is a 22mm diameter bayonet cap lamp. BC15, a 15mm base, can also be referred to as SBC standing for Small Bayonet Cap.
