Two BA15s type incandescent bulbs are used
as spot lights in bullet fixtures for reading lamps and other
The base of a BA15s bulb is grounded and is
a metallic 15mm diameter base with symmetric bayonet side-pins.
A single contact at the bottom provides a contact for the positive
The 1139 bulb dimensions are
width 1.38 inches
length 2.3 inches
The 1383 bulb uses the same base but measures
width 1.5 inches
length 2.6 inches
Both bulbs are frosted for better diffusion.
Operating specifications for the spotlight BA15s bulbs are
The 1139 is less power and used in shorter
bullet type fixtures. It offers the same luminosity as the low
power 1003 bulb.
The 1383 uses the power level of the 1141,
but with the inside reflector, provides a higher level of luminosity
toward the front of the bulb. It is often found in longer bullet
for detailed specifications of the bulb you are replacing.