Author Topic: LED's on 230V AC  (Read 4044 times)

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Vojta7

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LED's on 230V AC
« on: August 22, 2011, 05:38:21 AM »
Has anyone a working an simple schematic for 20 LED's to 230V AC? I need a current about 15 mA, voltage loss is about 3.2V per LED.

prasadbodas2000

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Re: LED's on 230V AC
« Reply #1 on: August 27, 2011, 10:58:57 PM »
A step down transformer from 230-250VAC to 12-0-12 V AC is a starting point, choose a 200mA rating on low voltage side. Use a full wave rectifier with a 1000mircoF capacitor. It will give you around 14V DC, then you can arrange for 5 parallel streams each of 4 LED in series. Better use a LM317 chip in a current regulator mode. (a simple circuit for LM317 is at http://www.otherpower.com/otherpower_lighting_leds.html )
Also go for 80% of the rated LED current i.e. 16 instead of 20 mA to get less heating and better life...
HTH
thanks and regards