I mean simple circuits.
But usually they always interact when you connect one simple circuit with another, but then everything changes. The votlage drop will change in both circuits, and the current also changes and that is the thing that always makes me panic. Because how much stuff can change by adding one component or changing one ccomponent.

That is one of the reasons for things like Thevenin equivalent circuits. If I give you a circuit that, at the output, behaves like an ideal voltage source in series with a resistor and another circuit that, at the input, behaves like a resistor, then it is a simple matter to determine what the voltage and current are at the interface when they are connected. Never mind that each has several dozen or even hundred components in them.

I also pretty often see random capacitors on many circuits that I usually don't understand or random resistors.

They may be there for any number of reasons. Capacitors are often used to filter power supply noise, but they can also be used to couple AC signals between two circuits or to create frequency-selective filters. Similarly, resistors may be there to limit the current or create filters or slow transition edges. Lots of other uses.

Also stuff like nonlinear makes me also confused. Knowing something about calculating and adding stuff like Norton makes my head spin.

Nonlinear circuits are not trivial. This is why we often break a problem down into two solutions -- the DC and the AC -- in which the overall solution is the superposition of the two. We then design the circuit so that the full-up nonlinear behavior is taken care of in the DC, where the analysis and design is much more tractable, while the small-signal behavior that we are primarily interested in is constrained to be a sufficiently small deviation from the DC solution that it can be modeled as a linear circuit within that region with sufficiently good results.

Take things in small steps. Someone doesn't learn to play a sport or a musical instrument or martial arts or auto mechanics by jumping in and doing the most complicated advanced stuff right from the beginning. Baby steps. Build the skills up incrementally. If you try to do too much too fast, you just end up digging a hole that you will become hopelessly mired in.

 

just a question but, how is this thread "off topic" ?

 

Are you sure this branch of science is for you? There is nothing wrong with revaluating your skills and interests and it may be prudent to manage expectations before you are financially committed.

I know some people who ended up being unemployable and/or miserable because they chose to study something they are not good at or thought it would be easy and now they have a massive debt that may not ever benefit them hanging over their head.

Just my opinion from what I've read so far..

 

Are you sure this branch of science is for you? There is nothing wrong with revaluating your skills and interests and it may be prudent to manage expectations before you are financially committed.

I know some people who ended up being unemployable and/or miserable because they chose to study something they are not good at or thought it would be easy and now they have a massive debt that may not ever benefit them hanging over their head.

Just my opinion from what I've read so far..

I thought about that.
But this is the only thing I was doing. So I don't know what to do if not electronics.

 

I thought about that.
But this is the only thing I was doing. So I don't know what to do if not electronics.

Then I recommend you start again with the basics. The textbook section of this website has good material. Do the exercises and simulate the results.

My favorite thing about electronics and chemistry for that matter is the never ending complexity. This is a bad thing for some people because the brain is always hurting

 

Then I recommend you start again with the basics. The textbook section of this website has good material. Do the exercises and simulate the results.

My favorite thing about electronics and chemistry for that matter is the never ending complexity. This is a bad thing for some people because the brain is always hurting

I'll try my best
But yea it isn't easy.

 

Stop repeating the basics. Start analyzing some more complicated circuits with an experienced person or jump in and start to design a project and see how it goes. Soon, you'll have a functional block diagram with 3 to 5 blocks, and corresponding circuitry with 5 to 10 capacitors and resistors in each and you'll soon say, "this wasn't bad - I know what each component does". By the way, many of the capacitors on a circuitboard for digital circuits are for power supply decoupling, to stabilize the voltage at each chip. Nothing special and there is generally on by each chip. Not a big mystery, not something that "the basics" will teach you, and half the "complexity" of those complicated circuits - solved. Get started, design something.

 

One thing I will say is not to overthink the problem. Passive components like resistors, capacitors and inductors always behave linearly according to the laws of physics. Sometimes components are there because its 'good practice' & no calculation is possible or needed. In time you will recognise things that can be ignored from a circuit's functional perspective and you will recognise common building blocks within larger circuits so, even without calculation, you will intuitively understand the basic properties of the arrangement.

 

1. Master fundamentals first. A good starting point may be the following course from MIT:

https://ocw.mit.edu/courses/6-002-circuits-and-electronics-spring-2007/pages/lecture-notes/

2. Complex circuits are usually made from “blocks”. Interactions blocks are intentionally kept simple.

3. Learn using approximations and intuitive design - great tools to overcome complexity.

4. In well designed circuits every element is there for a reason (and has a value for a reason).

5. Final circuit may look complex, but inside it there is often a simple skeleton design; it is “decorated” with additional elements or blocks to resolve specific issues.

 

You can read and read and read about the fundamentals of baseball, hockey, soccer or what ever. You never really learn to play until you get out on the field. I would ignore all advice to re-study and re-study and master this or that. Just start doing. A journey of a thousand miles only starts when you take the first step - no matter how much you prepare. Start walking.

 

From reading many of your posts I get the feeling that you regard circuits as abstract mathamatic abstracts.They are not. If you start from the other end, building simple circuits and getting them to work, you can bring the real aspects of circuitry to meet the models you currently embrace. Many people became involved in electronics by making and debugging things. If you are considering electronics as a career hands-on experience in the part of field in which you seek work will give you a leg up over some of the competition.

I highly recommend you choose an analog circuit to build and debug, and do some of your own modifications and experiments along the way. For example, you cannot place your hand next to the tank of a VHF oscillator and see the frequency shift using SPICE unless you already know how to model it. "Hands on" experience will give you a little intuition about how given circuit work and are affected by variations in components and environments.