led with proper resistor before it.

Good start. If you change the resistor to 150 Ohm the LED will have its specified 20mA current.

Like Robert said, great start! I'll help you learn how to get the answer he gave. Ohms Law is V=I×R (Voltage = Current × Resistance). You are supplying 5V to the circuit, but your LED uses 2V so 5-2= 3V. Your LED is rated for 20 mA, so you have your voltage and current and now you can solve for resistance. Solving for R=V/I, so 5V ÷ 0.020A = 150 Ohms. This is the most important equation for basic electronics. It will help you build many cool circuits 😉

Sorry, the "most important equation" suppose to be this (5V - 2V)/0.02=150Ohm

Valid correction :-). Unfortunate typo by Alpha who was kind enough to take the time to help.

From my reckoning, Alpha looks to be correct, 150 ohms gives 20mA, this is confusing, as lm no expert either!!!!!!!

Do this world needs Bootlickers?

R= 150 Ohm

OK I've changed the resistor and the led is now at perfect brightness - thanks everyone - I see the practical use of ohms law now. :-)

I'm sure everyone's intention’s were good here, but l think, if you are going to offer info about a circuit, then you should double check your figures before putting them out, those of you who are experienced with calculating these values, will sometimes take it for granted that even beginners know the very basic stuff, and wil skip over it, but to really help, it would be better to make it clear about the calculation ie: 5v minus the 2v drop from led, so, 3/0.20=150ohms, Alpha did give correct value, but it was confusing when he stated: 5/0.02=150ohms, l presume because he is experienced in these calculation, he just took it that everyone would realise that he meant (5-2)/0.020=150, because if you calculate 5/0.020 you get 250, so for a beginner, this throws you right off course...! The most annoying thing about this thread is that, Robert_kidd gave the correct value, then along comes hurz, who corrected Alpha with the right formula but wrong calculation, of 1500, then Robert agrees with hurz that it should be 1500. As l said from start, l'm sure you all mean well, but please check your calculation before they go out as it causes a lot of confusion. Thanks...!

@Tedski. Now you are only adding to the confusion you so much wish to avoid. If you look carefully, you will see that hurz did indeed provide the right values.

Yes, l put my hands up, sorry to all of you, l didn't look at it properly, l mistook the capital "O" for a zero, l apologise, but you can see how easy it is for a beginner to get confused..!

I know, and do like to see kHz and not Khz

@hurz Thanks for correcting my mistake. I meant to put 3V since I already showed that calculation, but it would have been better to show all together as you provided. 😊

@tcab Awesome! Oms Law will help you with all your future circuit designs 😉