Attn: Elecrical wizards

[Flyinfool]

Yup!! There's your problem!!! 330 ohms is Orange Orange Brown for first 3 markers. 330,000 ohms is waaaay too much resistance! OK now for today's class...

 

First, the resistor color code:

 

1 = Black

2 = Brown

3 = Red

4 = Orange

5 = Yellow

6 = Green

7 = Blue

8 = Violet

9 = Gray

0 = White

 

To remember this, Bad Boys Rape Our Young Girls But Violet Gives Willingly. First letter of each word relates to the color.

 

To read the "code", the first color is the actual number as is the second color. The 3rd color is the multiplier or number of zeros following the first two numbers. The other bands are for tolerance, silver is 10% +/-, Gold is 5%, etc, other bands can be for wattage or temperature coefficient and other technical junk you don't need to worry about. Wattage rating is often the physical size, which brings us top the 2nd part of today's lesson, Ohm's law, etc.

 

I = Current or amps

E = Electromotive Force, or Volts

R = Resistance in ohms

 

Volts is a electrical "pressure" or force

Current is a rate of electrical flow or the number of electrons that physically pass a point in the wire per second.

 

Basic ohms law, E = IR, I = E/R, and R = E/I. With the same voltage, the more the resistance, the less the current in a completed circuit. If the circuit is not complete, you can put one end of a bazillion ohm resistor on a battery and until you put the other end of the resistor on the other end of the resistor on the other battery terminal there will be no current flow, therefore with a voltmeter you will read the full battery voltage between the unconnected end of the resistor and the other battery terminal because there is no current flow which means no voltage drop across the resistor (no IR drop across the resistor).

 

Watts is actual power or load across the supply. P (Watts) = IE. With a constant voltage, the more current you draw (also the smaller the resistance) the more power you use. Now seeing as the average LED draws around 20 milliamps give or take (milliamp is 1/1000 of an amp) then the power draw is going to be 0.02 x 12 or 0.24 watts. Double that for a safety margin and a 1/2 watt resistor should suffice...

 

OK Bob, now stop messin with us.

Your colors chart is off by 1

Black is zero not 1 white is 9 not zero.

 

Normally your description of power is correct. But there is more to consider with LEDs.

There is no such thing as a 12V LED. What the manufacturers do is to build in whatever resistor is necessary to operate the LED in a 12V system which is really a 14V system with the engine running. As for the current draw, with modern LEDs that are series parallel circuits the 20mA per LED does not apply, you have to check the manufacturers specs. I added 180 LEDs to the back of my bike and the whole batch draws 1 amp at full brightness, that works out to 5.6mA per LED.

 

In this case he is using the resistor to dim the LED, so the resistor is not dropping the full 14v. with the LEDs that I used on my bike the 330 ohm was dropping ~5V so 5 x .02 = .1W so again the 1/2W resistor has plenty of headroom.

 

I think I really cornfused thins now.

[Thom]

There's a Appt for that ElectroDroid android store , it's free !

[djh3]

Way over my head dude. Maybe I can dazzle you sometime with my knowledge of military cargo aircraft or differentials or something. Eletricity aint my bag. I can struggle thru some stuff but all the ohms laws etc is why I pay my $12 a year. lol If we share our knowledge amungst us then knowbody has to know it all, right? Should be able to finnish the back half the bike, lights on crash bars by bags and the additional light on the back. I am going to replace the reflectors up front, but I know I have to split the fairing probably and I have a Buddy Rich cable comming, so I'll kill multiple projects then.

[Flyinfool]

I was afraid that between Bob and I we had your eyes spinning in counter rotating circles.....

 

Funny you mention military cargo, I just got off the phone with a friend that is a load master for every cargo plane the AF has.

[bongobobny]

Yes Jeff is right, the numbers should start with zero and end with nine. My bad, I'm getting old and senile!! I'll fix it later.

 

Jeff, I based my approximate current draw on the lights he bought which have 3 led's in them if you look at his picture...

[djh3]

Partially my fault. I thought I put a link to the actual lights I put in and it had all the specs etc. .06 amp draw Made in USA, 10yr warrenty. Found on e-bay here. They come in clear lens, red or amber. also black or chrome outer housings.

http://i.ebayimg.com/t/USA-MADE-Tecniq-Red-Clear-LED-Clearance-Side-Marker-Light-1x4-Camper-Trailer-/00/s/MTIwMFgxNjAw/$T2eC16h,!)!E9s2fDwrYBQkTifl!Bg~~60_57.JPG

[djh3]

Worked on hooking the fronts up some today. Looks like they will be pretty simple. No cutting or splicing of wires. Just need to build 4ea "y jumpers". Plug one end into the power to lights and split it with Y so I can power OEM light and my new lights. I have the power wire running along the brake hose on the back side with a couple little zip ties.

[djh3]

Finnished today. Heres some pics. Actually the wife and I went for a ride this evening and they look pretty dang good in the dark.