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Powering LED(20mA) using AC supply

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Naveed Ahmed

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I have an application to power up the LED using 220v AC voltage source.


Consider the following circuit.

Line---------------R1-------LED-----------Neutral


R1=1Mega ohm


Will it work??
Or i have to make voltage divider circuit??

Guidence is needed

Naveed
 

You need an antiparallel diode at the LED to keep the reverse voltage rating. Or use a small bridge rectifier to save 50%
of input power. Or an RC series circuit instead of a pure resistive ballast to save even more power.
 

nice dear.

20mA LED using 220v


so V=IR
R1=220/0.02=11K

R should be 1M?? or R should be 11K?
 

11K is correct, but you need a bridge rectifier to get 20 mA at the LED. And the resistor must be rated for 5 W.
 

hi
yes it must be 11K OHM but power for that resistor abt 5WATT
u like use small heater in ur circuit its better to use capacitor
method to drive ur led
 

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