most common form factor of light bulb
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What is an A19 bulb?
When picturing the shape of a light bulb, the A19 usually comes to mind. You may see it referred to as an upside-down pear-shaped bulb. Though A19 bulbs were originally designed for incandescent technology, you can now find a wide selection of LED versions that function at a much lower wattage. This means they consume much less power!
They often use a standard screw base, the E26 base. The E26 base, also known as the medium base, works in most residential applications. Less commonly, you may find A19 light bulbs that use an E12 candelabra or GU24 pin base. The candelabra base also works as a screw-type base but features a smaller diameter than the E26.
The number next to the ‘A’ refers to the diameter of the bulb in 1/8 of an inch so as that number increases, so does the size of the bulb.- This means an A19 bulb measures 19/8 or around 2.375 inches in diameter.
- An A15 should measure around 15/8 or 1.875 inches.
- An A21 measures around 2.625 inches around.
To learn more, check out our buying guide The Anatomy of the LED Light Bulb!
Where can I use a Sylvania A19 bulb?
Use LEDVANCE Sylvania bulbs anywhere from commercial offices and restaurants to residential kitchens, living rooms, and bathroom spaces. You can use them in desk lamps, porch lights, wall sconces and most household lighting fixtures.
Want to replace that old 60W incandescent in your desk lamp? Why not try an 8.5 watt Sylvania A19 lamp?
Need a festive bulb for the holidays? Maybe you want a fun color to change up your fixtures? LEDVANCE Sylvania offers a colorful line of A19 LED bulbs, like this 8.5W green bulb, that are suitable for damp locations.
My mom has an old ceiling fan that we're trying to find replacement white bulbs for. She bought a couple of packs of bulbs and the base was too small. The pack says they are A15. Does the 15 mean 15mm diameter of the base? That's what I thought, but I measure 10mm and the pack is sealed. Either the 15 doesn't mean what I think it means or the bulbs were packaged wrong from the manufacturer. I took one bulb out of the fan and it actually measures 15mm diameter for the base. I'm lost on what bulb to order.