Need help with basic bluetooth speaker build
You are quite welcome. And please, don't hesitate to ask questions. That is how we learn.
Your first inclination is correct, the load determines the current. Specifically, the load determines the current for a specified voltage. That is: for a specific voltage, the load will only draw "X" amount of current. With the LED strip you've selected, the designers have current limited the (6) sections to not exceed 1.45 Watts By using a single resistor or multiple resistors to keep the current low enough. I would like you to look up Ohm's Law triangle. This will help immensely in getting a handle on the relationship between the main components of electricity - Voltage (V), Current (I), and Resistance (R). Basically it is V over I times R. If you cover the one you wish to solve for, it shows you the direct formula you should use.
Now in your application, you need to know one more thing from what has already been calculated. You know the max wattage of your strip and the voltage, now you need to know the actual current it will draw. So 1.45W / 12V = ~0.120 A, or 120 mA. Since you have 6 sections making up that strip, that means each section takes up 120/6=20 mA (0.020 A). Now, you have V and I, and you want to know R, so you use V/I=R or 12 /0.20=600 Ohms. So each section is limited to 20 mA by at least a 600 ohm resistor., I know, math. But it really comes down to that. And that is what the manufacturer does to ensure reliable operation of their product for the intended voltage, it will never draw more current than that if you stick to 12V and that circuit remains intact.
There are some good books out there, and there's a lot of good online stuff. I'd have to go back through and see what's appropriate for a beginner, or neophyte if you prefer. I'm on vacation atm, so it will have to wait untill I get a chance to access my home again. Until then, I suggest looking at the YouTube channel LearnElectronics. Paul is a nice guy who wants to teach others.
As for myself, I've been playing with electricity since I was 7. I'm 55 now, and I still have the first thing I made, an electromechanical buzzer. If I cleaned it up, it'd still work. Most of what I learned, I read. My school fell through on the electronics program in my latter educational years, so I went it alone. I'm still learning, and I love it.
Thankyou for that in depth explanation, im learning a lot just from this one speaker build, its the first time ive had to add any type of LED accessories to something ive built so hopefully any future builds will be easier for me after this one is completed. Ill definately have a look at the youtube channel you suggested, so thanks for that, if in a few months time i can feel confident about making circuits or even just working with these amplifiers and adding things to them without an issue ill be happy lol. And yeah i had the same problem at my school, the tech department was a waste of time, so i never learned how to do any of this, and given my trade is fabrication and welding i never needed to learn it for work either.
Made it home and found the book that really helped get me going deeper into it rather than just following a kit. It's called Electronics The Easy Way by Rex Miller. I linked the one I have. There are newer versions if you'd want to be more up to date, but the best thing to do is learn the basics first. That way, going further is much easier to understand.
Thankyou for that, ill definately buy it and have a good read. No doubt ill still have to come on here at times and ask qustions at some point though, if only to check my designs for any fualts so i can be sure im on the right track
That is awesome. Feel free to run theoretical questions by us as well. Or just design questions in general.
Oh i have tonnes of theoretical questions lol but thanks to you all for being around and being willing to help us newbies when we need some advice, things go a lot smoother with your input