I'm a n00b^2 in the electronics world. Although many resources teach what each specific electronic component does (capacitors, resistors, diodes, etc), I have yet to find a "Why?" or "How?" as to the process of how one goes about designing their own circuits from scratch.
How do you know when/where/how many capacitors, resistors, diodes you need in a circuit, and at which junction points, where you need what in series/parallel?
Now before I get slapped -- I realize that this knowledge is absolutely something that comes with experience, and much research and understanding of electronics and electricity. I also understand the basic purposes of each component, but I don't know how to go about implementing them into my own circuits. I get dizzy when I look at a circuit board of a seemingly simple circuit/project see the 10's/100's/1000's of components that are reaching across the board, and especially connecting to multiple, separate components and points (the ever-tangled web of parallel circuit design stumps me).
What I have so far:
Let's say I want to design a motion-activated webcam. Well, first step, I'd work "backwards", because you never "start" with capacitors/resistors, as they're merely to clean and prepare voltage for the real "performers". So we'd need the two main functional components of the actual webcam (the action/output), and the motion sensor (the input).
Now for those to work, they need electricity. So I'd find their voltage/amperage requirements (still working "backwards"). Then based on their ratings, I'd pick out some components to properly limit the voltage/current to them (through resistors and voltage regulators).
Then I'd need a "switch", or a junction between them like a transistor.
I suppose that'd pretty much complete that circuit? But whenever I see even small hobbyist projects and circuits, it seems like they're just randomly painting the board everywhere with capacitors and resistors, and through such an expansive, almost "untraceable" web of parallel connections.
Can you share your process of how you plan and go about designing a circuit from scratch? And do you ever use software to plan and map your circuit design out?