I was looking at your general LED How-to at cardomain, and I have had a few electrical classes so I understood it just fine. What I have always been told is that LED's are wonderful things because you can leave them on forever (car being on or off) and it will never kill your battery, but after reading that article you had on there. My question is what draws a battery down or kills a battery? Is it the Volts being pulled off of the battery or the amps?

Because, from the looks of it, you had in the example 9 volts running off the battery, would that draw the battery down? Because the way I understood it (probably not right) is that that would leave 3 volts to try to run the rest of the system on. Or is it the Amperes that draw from a battery and because there is only 20mA than it will make no difference to the electrical system?

Just wondering, so I can try to wire these up too :) Thanks :D

 

It's not volts, but amps, Ryan, as you probably have suspected. The volts thing is confusing.

Basically, look at this way: volts is a measure of electrical PRESSURE, and amps is a measure of electrical FLOW. If you have a tank of water, and you look at the pressure at the bottom, you have pressure but no flow. Put a valve on, the valve "sees" the pressure, but until you turn it on, there is no flow.

LED's WILL eventually draw a battery down. The 0.020 amps of drain or so per LED is small, but enough of them, or leave them on long enough and it can have an effect. For most of us that start and run our vehicles fairly often, it's not a real problem

LED's in series are most efficient! 3 LED's run in series still only draws 0.020 amps. It's not a contradiction. In the single LED circuit you were wasting most of the power in the resistor. In the multiple LED circuit the resistor does less and the power you would have wasted instead lights additional LED's.

Power, by the way, is volts times amps. It's the measure of actual work being done. In our "typical" LED case, 12 x 0.020 = 0.24 watts or about a 1/4 watt of power total.

Hope that helps a bit, and ask for further clarification as required.

 

Thank you very much! :D

That helps a lot, yeah it had me a little confused but I got it now :D

Thank you again!

 

5011-302 - Circuits I w/ your instructor, professor J.Griggs..

 

What a simple PM would have done just as well...

 

Speaking of PM's -- are yours working now? I tried to PM you back around the time the site opened about the valance and they weren't active. I'll try to PM you later. With recent events and all, I won't be able to do anything with it until after the holidays.

 

That would have helped 1 person. This way many people have access to the wealth of knowledge that is Daddy Griggs. I, for one, was interested and enjoyed reading and learning.

 

See I was trying to help the community as a whole. :)

 

You're a good man Charlie Brown!