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use step down transformer.220-12V ,bridge rectifier,and voltage regulator IC (7805).
LEDs should be isolated from the main supply, so if size-constraints are not an issue, get a proper LED driver. Or you could just wire each LED in series. Each one requires about 3.6V at full brightness, so with 220V, you will need about 65-70 LEDs and a 250mA or smaller fuse. The LEDs should be connected to a small isolation transformer so they are not live with reference to ground. You may want other forms of protection as well, like a resistor and a over-voltage shunt. If you want to light up just a few power LEDs, I recommend buying or building a proper driver. Often constant current supplies are used.
From mains (hot) a 2200Ohm resistor in series with a 220nF capacitor.
See that as part 1
In series with the LED a 220Ohm resistor and a diode in reverse polarity to the LED parallel to LED and resistor - so the diode connects to one end of the resistor, from the to the LED and the other leg of the LED back to the diode.
See that as part 2
The output from part 1 connects to one side of the diode in part 2 and the other side of the diode back the mains (neutral).
The capacitor limits the current for the circuit and the resistors take care of the voltage and current for the LED.
The diode is anti parallel to the LED to protect the LED from the reverse voltage from mains as we don't use a rectifier.
I am not good with drawing, so I borrowed a corresponding picture from bwir.de
Credits for it go to them, not to me, but I can give you the required calculations if you need to adjust the circuit to other LED's.
Huh... isn't that only a half wave rectifier though?
Not it is not, it is only revers polarity protection diode.
You wanted it simple, and I don't know of any way with less parts to make it work.
Using a rectifier and DC means a whole bunch more in parts and it will cost more than to buy a night light with LED (and they use a similar circuit anyway).
At 50Hz some people claim they can see the light flashing but I found this to be true only for flouroscent lamps.
The only LED's I have seen "flashing" on those circuits are the yellow ones and onyl if there was a flouroscent lamp near by.
Posted:Aug 14, 2014
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