This is a GU10 style lamp for 12V use, ideal for situations where a mains lighting system has been converted to 12V. The driverless design makes them compatible with PWM-based or voltage-based dimming. An integral diode bridge allows insertion in either orientation. They are made with standard FR4 PCB rather than Aluminium for lower cost.
This is a KiCad (5.1.9-0-10_14) project.
Gerbers, schematic & BOM may be found in the outputs directory.
After production, a sandwich of M3 30mm (or shorter/longer, depending on your fitting depth) standard cap-head machine screws, bolts and washers can be fitted through the central holes to produce GU10 compatible "lugs" for insertion into a standard GU10 bayonet lamp holder.
For outdoor use I'd suggest conformally coating the boards on the top and bottom sides after insertion of the M3 fasteners.
These lamps are for 12V DC only. Do not connect these lamps to mains voltage.
Standard 2835 LED chips are used (I used 3000K 150mA 2.95Vf CREE J Series® JB2835AWT-W-U30GA0000-N0000001). LEDs are in 4 groups of (3 chips in series) with a resistor for each group, with each group seeing a ~11V supply voltage after the diode bridge drop. I'd recommend using 39Ω 2512-size resistors (for a LED current of 50mA) and a total system current of 200mA (~2.4W including power dissipated by the diode bridge). The lamps stay at a sensible temperature at this power.
- Issue A - Initial release (used in the example photos above).
- Issue B - Improved layout for better thermals.