Yesterday I bought a LED lamp supposed for 230 V 60 Hz AC with a built-in rectifier to 40 V DC 280 mA.
I decided to guess the approximate circuit schematic. Since I have no idea how many LEDs modules it consists of, I have assumed eight.
The schematic includes an AC source with a standard room switcher and smooth AC/DC rectifier.
Since I wanted to prevent the LEDs from flickering, I opted for a capacitor that makes the current flow reasonably smooth.
The LEDs indeed flicker a bit. However, this is due to the capacitor capacity set to limit values. If I set the capacity any higher, it will take the lamp a longer time to switch off.
I am a complete rookie to circuits so I may be completely wrong :-)
There are two switches:
1) the one next to the power source is the "room switcher."
2) the one next to the capacitor is for experimental use - switch is off to see how the waveform changes without the capacitor.