Which base type does not belong among bulbs commonly described in the material?

Which base type does not belong among bulbs commonly described in the material?

• A. Single pin
• B. Edison Screw
• C. Bayonet
• D. Bi-pin

Answer: (A)

Understanding how bulbs connect to their sockets helps explain why one base type doesn’t fit with the others. Bulbs are described by the way their base mates with a socket—the connection mechanism to deliver power. In most lighting materials you’ll see three common families: Edison Screw bases, Bayonet bases, and Bi-pin bases. Edison Screw is the familiar screw-in style that uses a threaded shell and a bottom contact. Bayonet bases use two small pins on opposite sides that insert and twist into slots to lock the bulb in. Bi-pin bases have two pins that push into matching spring contacts in the socket, used in many halogen and some LED applications. A single pin base isn’t part of this standard classification because bulb bases are built around providing two electrical paths through the connection method—either via the shell plus a bottom contact (screw), or via two pins (bayonet or bi-pin). That makes single pin the outlier among the common base types described.

Understanding how bulbs connect to their sockets helps explain why one base type doesn’t fit with the others. Bulbs are described by the way their base mates with a socket—the connection mechanism to deliver power. In most lighting materials you’ll see three common families: Edison Screw bases, Bayonet bases, and Bi-pin bases. Edison Screw is the familiar screw-in style that uses a threaded shell and a bottom contact. Bayonet bases use two small pins on opposite sides that insert and twist into slots to lock the bulb in. Bi-pin bases have two pins that push into matching spring contacts in the socket, used in many halogen and some LED applications. A single pin base isn’t part of this standard classification because bulb bases are built around providing two electrical paths through the connection method—either via the shell plus a bottom contact (screw), or via two pins (bayonet or bi-pin). That makes single pin the outlier among the common base types described.