Here's the basic formula's for ohm's law.
v = i x r
r = v/i
i = v/r
i just have some basic questions..
how are the led
's arranged ? are they in series or parallel ?
from the sound of what you did, you might have them in series. if they are in series then you don't have enough voltage present to lite up the leds or even get them into saturation (a fancy term, that means they turn on, or lite up). in series voltage changes per component, and current is deadlocked, so what that means is you will need to have 4v for every led
you're using. however if you arrange the circuit in parallel, you will have all the voltage you require, in parallel voltage is deadlocked in the circuit, while current changes per componet.
depending on how they are hooked up in the circuit, one led
might have been doa, or burned up on assembly (led
's can only take a few seconds of extreme heat, from a soldering iron before they melt internally), the best way to figure it out is use a 2 AA batteries, and try out each led
. i am assuming though you have blue leds, probably in the 4000mcd range, they go into saturation around 3.5v and top out at 4.3v so you need to get your supply voltage in the range, or pretty close to it, anything manufactured has a tolerance, and are never face value or follow the theoretical values. (resistors are a great example, the 4th color band is for tolerance, gold = +/- 5% ; silver = +/- 10% ; no 4th color band = +/- 20%)
so here's what i suggest you do,
1. make sure your dc
2. make sure you have the dc
transformer hooked up right, if it happens to be a recycled dc
transformer (from a cd player for example) the wire that has a white band running down the length of the cord, is the neutral portion (or ground).
3. if the circuit is still a no go, rig up 2 AA batteries and try out each led
, like pc
suggested, if they are fresh akl. batteries you should be able to squeeze by with 2, if they been used, you might want bump it up 3 AA batteries (1.5 x 3 = 4.5v)
4. if all the led
's lite up with the battery, rebuild the circuit, then get access to a voltmeter (or multimeter) and run through the circuit, checking the voltage from the transformer then to the rest of the circuit. if can you spring for it.. HD
has multimeters for 20, and walmart has them for 10-15. both stores have great return policies..
i am electronics major, so if you need any help let me know, i can run you through the basics, and give you some ideas how to build this circuit, provide wiring diagrams, ect ect. just let me know.