Its actually a hack and a concept of reuse of scrap. I have a 4 LED night bulb and a spare not working adapter. I took out the actual components out of bulb and then replaced it with faulted PCB of adapter and I again got a 12 V adapter which I basically used to power 12V LED strips.
In below circuit diagram you can make one more change. We got two points for input P and N, you can insert a resistor of low value and High wattage like 1/2 Watt to use as current limiter with point N...I have 220 ohms in my circuit.
You can use 1M ohms if you dont have 820K ohms.
The next circuit is more safe and you can use it for 12V generation also.
Also be careful while testing the circuit, its 220-240V AC not DC, its dangerous.