need help

Community Projects
1

picture A >> series connection of a supply voltage and led.

picture B >> series connection of a supply voltage , led , resistor.

picture A - i think the LED will get burn.

picture B- LED wont get burnt.

question : why picture B wont get burn?

can anyone here help explain?

what will happen if the supply voltage in the picture is 220v is it ok to use 0.1ohm resistor?and what if the resistor is 1Mohm , is it ok to use 0.1v as the supply voltage?

2

uhhh…what?

3

If you’re asking why an LED won’t light up with only .1v as the supply, well,

http://lmgtfy.com/?q=led+minimum+voltage

4

Have a look at this tutorial. It will take you through the basics.

https://learn.sparkfun.com/tutorials/li … the-basics

If you need to use power as high as 120, or 210V you should be regulating your power down to say 5V so that you don’t have to limit the resistance so much.

https://www.sparkfun.com/tutorials/57