Problem in connecting LEDs in series and parallel

[Ramesh_maharjan]

I having problem in connecting the leds in series and parallel. I have used the same kind of LEDS(one color from same manufacturer) and calculated the resistor value but in practical but it got wrong.
The main problem is each LEDs glowed with different brightness. How can I make it glow with common birghtness. I have found that the LEDs form same manufacutrer can differ from one another and can draw variable current for the same bightness. What should I do it to reduce this problem

 

[IanP]

Try to increase current flowing through diodes to, say, >10mA ..
Above certain current levels the difference in the brightness should become almost invisable ..
Here you will find more explenations:
**broken link removed**

Regards,
IanP

 

[czn]

in general,the brightness of the LED is decide on manufacturer
the brightness and the resistor value will have different form same manufacutrer
When the resistor value are different,the current of the LED will are different in parallel,it will make the brightness are different.(because LED is current drive device)
so suggest using series method

typical the LED's current is 15mA