Civinfo - View Single Post - Calculate the resistor you need for a LED

neilfs · 3rd March 2007, 11:52

Cool, thanks guys - I'm learning something which I've always never really understood properely. It is actually very basic.

Okay, silly question, just so I fully understand the reason why you always put a resistor in each circuit...

So why would you not just put four leds in series? 4 x 3 = 12V

Or is the purpose of the resistors to protect the LEDs from over voltage if you cannot guarantee a stable 12v supply?

Okay, next silly question.

Of the two examples in the diagram, which one is most battery efficient, draws the least amps, or are they both equal?

Thanks!

3rd March 2007, 11:52	#6 (permalink)
neilfs Supporter Wheelnut Join Date: 18th November 2006 Location: Hindhead, Surrey Posts: 73 Thanks: 2 Thanked 0 Times in 0 Posts iTrader: (0)	Cool, thanks guys - I'm learning something which I've always never really understood properely. It is actually very basic. Okay, silly question, just so I fully understand the reason why you always put a resistor in each circuit... So why would you not just put four leds in series? 4 x 3 = 12V Or is the purpose of the resistors to protect the LEDs from over voltage if you cannot guarantee a stable 12v supply? Okay, next silly question. Of the two examples in the diagram, which one is most battery efficient, draws the least amps, or are they both equal? Thanks!