Help!

[erospawn]

(12-31-2009, 01:29 PM)Wombat Wrote: Thanks for those link's especially the last one there and also the picture you posted.

OK,i like the look of the one shown as series in that last link.So if i'm reading it correctly and i use 8 LED's in this fashion each will have 1.5V running through it.Heres where i'm lost again,the LED's are listed as 12V so will they run having just 1.5V going through them?I've purchased them just off of evil bay and heres a link to the one's i'm getting.It doesn't say anything about resistor's,they are just pre wired,but it does say something about there power being 0.2W.

http://cgi.ebay.com.au/20X-5mm-White-LED...2c52566a05

Another thing,as it'll just be one transformer powering not only the LED's,but the two halogen's also,wont they have to be taken into account when working it all out or don't they effect anything whats needed for the LED's?

Here i was thinking i could just hook it all up and it'd work!

If wired in parallel, you won't have to worry about voltage.. current will be determined by the resistor wired to each LED..

Series... the voltage drop is the total voltage across all LED's...
3 LED's = 10.2 volts. with 1.8 left over.. so, that will be the voltage over the resistor.. so, again.. voltage / I = 1.8v /.025 = 72 Ohms..

Putting 4 LED's in series ( 3.4 * 4 = 13.6) probably won't light brightly, if at all.. So, you could wire 3 in series.. and then add the extra one wired in parallel..

LED's are basically DIODES... which means almost 0 resistance.. Current is what makes things happen.. You can have 50,000 volts with .000001 amp and not get hurt at all..

---- 3.4v ----- 3.4v ------ 3.4v ----- 1.8v ® ----- 12Volts
|
---- 3.4v ----- 8.6v ® ------------------------------|


PS..Based on that Link , you bought LED's with resistors already attached.. So, just wire them in Parallel... IN otherwords, each LED Anode is connectd to 12 volts..each LED Cathode is wired to ground.

+12 --------|
@
(-) --------|