Match the base code on the bulb and fitting before comparing brightness or smart features. A shape such as A19 describes the glass or plastic envelope; E12, E14, E26, E27 and GU10 identify different connections.
Quick base chart
| Code | Connection | What to verify |
|---|---|---|
| E12 | Small Edison screw, nominal 12 mm diameter | Exact E12 socket; not E14 |
| E14 | Small Edison screw, nominal 14 mm diameter | Exact E14 socket; not E12 |
| E26 | Edison screw, nominal 26 mm diameter | Supply rating as well as socket |
| E27 | Edison screw, nominal 27 mm diameter | Supply rating as well as socket |
| GU10 | Two-pin twist-and-lock | GU10 fitting, clearance and supply requirements |
Use the chart as an identification aid
With power isolated, read the marking on the fitting and the old bulb. If a code is missing, consult the fixture documentation or a qualified installer rather than forcing a similar-looking base into place. The chart identifies connections; it does not approve an adapter, decide the supply voltage or prove suitability for an enclosed fixture.
Then check the rest of the replacement
Measure the space inside the shade or recess, including the height and width of the bulb envelope. Compare the permitted electrical load, dimmer compatibility and intended environment. A base that fits mechanically can still be the wrong replacement. In the current Yeelight catalog, the GU10 family is a separate choice, not a substitute for an E12 or E27 socket.
Frequently Asked Questions
Does E27 tell me the bulb’s brightness?
No. The base code identifies the connection. Check light output and the rest of the product label separately.
