What’s a standard lamp holder?
The medium E26 standard lamp holder is the most common light bulb socket. It is used in most incandescent, halogen, CFL, CCFL, and HID light bulbs.
standard lamp holder IEC 60238:2004+AMD1:2008 This International Standard applies to standard lamp holder with Edison thread E14, E27 and E40, designed for connection to the supply of lamps and semi-luminaires only. It also applies to switched-lampholders for use in a.c. circuits only, where the working voltage does not exceed 250 V r.m.s.
The mogul E39 standard lamp holder is found in larger sized light bulbs, such as high wattage HID.C9 Bulbs have an intermediate or E17 base. These are historically known as the old Christmas light bulb size.
Medium Bulbs have a E26 standard lamp holder (E27 in Europe). This is the same size as a standard household bulb.