Howw to use high votage 220V for LED without transformer?

[thien]

High voltage with LED?

Does anyone know how to use high votage 220V for LED without transformer? I assembled some boards (collected from internet or newspaper), but not successful. Normally, capacitor is exploded after about 12 hour. Thanks!

C: .22 (400V)
R: 1K1W

o---------/\/\/\/\/\---------LED ......... LED---------| |-------o

 

[IanP]

Re: High voltage with LED?

For 10mA of current at 230V/50Hz you need a capacitor of 0.15µF.
Bear in mind that this is alternating current so you need a diode (can be 1N4148 or similar, or another LED) connected back-to-front in parallel with this LED ..
You can use a resistor in series and this is like connecting a fuse .. for single LED use 100Ω rated for 0.1W ..
And, 400Vdc or 250Vac caps should be just fine ..
Regards,
IanP