I am looking for a website where I can ask questions related to circuits, I hope I can ask them here.

I am reading All-in-One Electronics Guide by Cammen Chan and there is a confusing text about non-/ideal voltage and current sources.

Should I understand everything and only then continue reading or can I skip few thing? I don't know and that is why I am here.

What I hope for, is a person with time and knowledge, that can explain he basic idea of this paragraph. I am sorry to the wall of text...

He writes so often non-idea, ideal, not-so-pefect world, finite intenal resistance, input, ouput...

If you can only answer one question, please tell me what input is in a voltage source.

"If node A is the output voltage, input would be the same as the output."

V goes into node A, and 5 volt leaves node A. Input is negative terminal?

Page 44, title DC Circuit:

A non-ideal voltage source can be viewed as a voltage divider. Figure 1.22 .

If it were an ideal voltage source, internal resistance would be zero Ω. The

voltage at node A will be exactly the same as voltage originating from the voltage source. If node A is the output voltage, input would be the same as the output.

In a not-so-perfect world, voltage source would have finite internal resistance. This finite resistance originating from the voltage source makes the circuit look just like a voltage divider.

__Voltage at node A is no longer the same as the original voltage source.__In a non-ideal

world, when you connect a voltage source to a resistor, the

__output will not be exactly the same as the input.__High quality power supplies offer extremely low internal resistance (still non-zero), and your

__output is “almost” the same as the input__. It’s for this reason voltage divider is seldom used as a constant voltage source. Using Figure 1.22 as an example, if the original voltage source on the left is 10 V, the intended voltage output is 5 V at node A. By design, we set both resistors to have the same values (voltage divided by half) so that 5 V at node A can be obtained. In reality, the voltage at node A won’t be

__constant__at 5 V. Firstly, any changes from the original input source will change the voltage at node A (again by the voltage divider action). Secondly, any change in the resistances (e.g., caused by temperature variations) will also change the voltage at node A. To achieve a more stable voltage output, low drop-out and switching regulators are used, which will be discussed later in this book.

To show you that I tried to understand the text by myself, here are my notes on the paragraph which I don't quite understand, after that I post whole Paragraph.

Ideal voltage source:

Zero internal resistance

Non-ideal voltage source:

Non-zero (finite) internal resistance

non-ideal voltage source (VS) = voltage divider

If ideal Vs = internal resistance 0 = V node A same as VS.

"If node A is the output voltage, input would be the same as the output" (what does input does in a VS? The black lead of a laboratory supply? Negativ terminal? The input can't be the same, the output Voltage is "reduced" by component, last node should have 0V.)

Non ideal VS is voltage divider, because of iternal resistance.

Sorry I can't write down my notes, because I have to many questions.

Looking forward for your answers.