Circuit Idea/Common Circuit Questions
When we see for the first time a circuit, our natural human will is to understand it immediately, to discern the basic idea behind it and to imagine how it operates. Thinking about the new unrecognized circuit, we, human beings, begin asking a chain of natural questions. Alas, browsing through various electronics resources we usually cannot manage to find answers to our questions. Regretfully, education suppresses our most human desire - to ask questions and to get answers to questions.
This page contains a list of common questions that we need to understand, improve and invent new circuits. In other page, we will continuosly add specific circuit questions specific circuit questions.
List of common questions 
The problem 
- What is the problem that the circuit solves?
- Where does this problem spring from?
- What are the simpler passive circuits, on which the new compound passive circuit is based?
- What is the more elementary passive circuit that is transmuted into the new active one?
- What is the relation between the old passive and the new active version?
- What are the same but previous circuit implementations (tube, transistor, op-amp, etc.)?
- Why has the circuit this structure?
- What is the sense of connecting the passive components?
- Why are active components added to the circuit?
- Why are the components connected in this way?
- Can (some) internal circuit points serve as inputs or outputs?
- What do the active components (tubes, transistors, op-amps, etc.) do in this circuit?
- How do the active components do what they do?
- Can we substitute the abstract active electronic components by equivalent electrical ones?
- Can we put ourselves into their place?
- What do we do to perform their action?
- Where the currents flow?
- What are the voltages of the circuit points?
General idea 
- What is the basic circuit idea?
- Where the circuit idea comes from?
- How the idea is been evolving through years?
- What are the problems in the circuit examined?
- What causes the problems? Is the cause internal or external?
- How do we improve the circuit?
- What additional components do we add to elaborate it?
- Can we create an almost ideal circuit?
- Can we reverse the circuit to obtain the opposite circuit?