Revealing the Ideas behind Circuits

Welcome to Circuit Idea!

This novel electronics wikibook is for creative students, teachers, inventors, technicians, hobbyists and anyone who is not satisfied by formal circuit explanations. It is intended for people who really want to grasp the basic concepts of electronics by relying on their human imagination, intuition and emotions rather than on pure logic and reasoning.





We treat electronic circuitry not only as a science, but also as an art. Inventing novel electronic circuits is a result of human fantasy, imagination and enthusiasm. Fortunately, abstract electronic circuits are based on clear and simple ideas, which we derive from our human routines. In order to really understand how circuits operate, we have first to reveal the basic ideas on which they are based. We just need to know what problem electronic elements solve, why they are soldered together, what they actually do in the circuit, how they do it, and more. As human beings, we just want to "see the forest for the trees."

Great circuit ideas are "non-electrical"; they are not dependent on the specific implementation (tube, transistor, op-amp etc.). The purpose of this wikibook is to reveal great circuit ideas, real truth about circuits. It just answers a simple but reasonable question:

What is the idea behind the circuit?

Circuit idea is composed of two main logically connected parts: in the first part (Creating a circuit methodology), we will create universal methods for unearthing the ideas behind circuits; then, in the second part (Revealing circuit ideas), we will use these methods to reveal the secrets of popular circuits. The second part is designed as a collection of exciting stories about odd circuits and the amazing electrical phenomena behind them.

Following a novel building approach, the book presents every new more complex circuit based on the previous simpler one. First, we will derive the most elementary passive building blocks from the basic electric circuits of Ohm, Kirchhoff, Thevenin and Norton. Then, we will use these "bricks" to build more complicated compound passive circuits. Further, adding active elements in accordance with suitable basic ideas, we will build various transistor circuits. Finally, applying the powerful negative feedback principle in all its forms, we will transform these circuits into almost ideal op-amp ones.

Circuit idea will also contain stories about circuit paradoxes, contradictions, conflicts, and building schemes to induce creativity in readers. Historical "excursions" will show circuit evolution through the years. Some of the most interesting circuit stories will be created by students during their exercises in the laboratory; they will represent famous experiments (like Ohm's law). Other stories will be derived from teacher's lectures and exercises.

Completed circuit stories [ edit ]

Philosophy behind the Book (relying on human intuition, imagination and fantasy)

How to Contribute to This Book (motivate, inspire and induce creativity in readers)

How to Create a Circuit Story for this Book (showing the circuit evolution by building and reinventing the circuit)

Involving Students from Technical University of Sofia in Circuit Idea Wikibook (a teacher's story)

Why Circuit Ideas are Hidden (why inventors, authors, lecturers, professionals and producers hide circuit ideas)

How to Hide Circuit Ideas ("useful" tips for beginning "idea hiders" - humor:)

How to Kill Circuit Ideas ("useful" tips for beginning "idea killers" - humor:)

Why Formulas Cannot Explain Circuits (their place is at the end of circuit design after intuitive explanations - humor:)

Passive Voltage-to-Current Converter (assuming voltage causes current)

Passive Current-to-Voltage Converter (assuming current causes voltage)

Deriving a Series Voltage Summer from Kirchhoff's Voltage Law (a dual story)

Building a Parallel Voltage Summer (by using more elementary circuit building blocks)

Walking along the Resistive Film ("inventing" various resistive circuits by reproducing the famous Ohm's experiment nowadays)

How do We Create Sinusoidal Oscillations? (an incredible story about the philosophy of LC tank)

How to Make the Simplest Transistor Current Source (a bare transistor with steady input voltage or current)

Voltage Compensation reveals the philosophy behind the op-amp inverting circuits with negative feedback

Op-amp Inverting Voltage-to-Current Converter (compensating the external losses by an "antivoltage")

Op-amp Inverting Current-to-Voltage Converter (compensating the internal losses by an "antivoltage")

Presenting the Op-amp Inverting Current-to-Voltage Converter in a More Attractive Manner

How to Simplify the Design of the Mixed Op-amp Voltage Summer (after Dieter Knollman's original design idea)

Revealing the Truth about ECL Circuits (switching voltage and current sources in the emitter)

How to Reverse Current Direction (revealing the truth about basic current mirror)

How the Wilson current mirror equalizes the currents (the first viewpoint at the legendary circuit)

How the Wilson current mirror keeps up a constant output current (the second viewpoint at the legendary circuit)

Negative Resistance is based on an old Wikipedia revision

Negative Impedance Converter reveals the idea behind the weird circuit

Negative Differential Resistance demystifies the ubiquitious phenomenon

Revealing the Mystery of Negative Impedance is a general story about the mystic phenomenon

Investigating the Linear Mode of Negative Impedance Converters with Voltage Inversion

Investigating the Linear Mode of Negative Impedance Converters with Current Inversion

Investigating the Bistable Mode of Negative Impedance Converters with Current Inversion

Deborah Chung's "Apparent Negative Resistance" consider the greatest misconception in the area of the negative resistance phenomena

Uncompleted circuit stories [ edit ]

Why Creative Persons are Unhappy (why "normal" people treat creative persons badly) <talk>

Reinventing a Full-Wave Bridge Rectifier (by exploiting the powerful bridge idea) <talk> <group 64a>

How do We Compensate the Diode Forward Voltage Drop? (introducing the passive compensation idea) <talk>

Can a "Diode" Current Mirror Exist? (trying to build a current mirror with a diode current-setting part) <talk> <group 66b>

How do We Build the Simplest Transistor Amplifier? (common-emitter amplifying stage) <talk> <group 65a>

How to Make the Simplest Transistor Amplifier Bipolar (the famous biasing idea presented as a voltage shifting) <talk> <group 66a>

How to Make an Analog Transistor Behave as a Digital One (building a transistor switch) <talk> <group 68a>

Building an Emitter Follower (in sequence non-electrical > electrical > transistor follower) <talk> <group 67a>

Building a Transistor "Zener Diode" (making voltage-stable elements by applying a parallel negative feedback) <talk> <group 64b>

Building a BJT Current Mirror (by applying a parallel negative feedback to the current-setting part) <talk> <group 67b>

Building an Op-amp Follower (in sequence non-electrical > electrical <talk> <group 65a> <group 66a> <group 67a>

Building a Parallel NFB Inverter (overcoming the common ground problem by a parallel voltage summer) <talk> <group 65a>

How Does an Active Follower Behave when Disturbed? (negative feedback systems overcome disturbances) <talk> <group 64b> <group 66a>

How Can an Attenuation Cause an Amplification? (non-inverting amplifier) <talk> <group 65a> <group 66a> <group 67a>

Creating Odd Circuits "without Input" (putting various resistive sensors in the feedback loop) <group 65b> <group 68b>

Formulating "Golden Rules" for Using Disturbances Put into the Feedback Loop <group 65b> <group 68b>

What Is the Great Idea behind Virtual Ground Phenomenon? <talk>

How to Make Perfect Components (an ideal diode, transistor, capacitor, "superconductor", etc.) <talk> <group 68b>

How to Make a Perfect Op-amp RC-integrator (obtaining an infinite capacitance)

How Do We Swap Circuit Inputs and Outputs? (revealing the philosophy of the phenomenon) <talk>

How to Transmute an Emitter Follower into an NFB Current Source (reinventing the famous circuit) <talk> <group 68b>

Revealing the Secrets of 741 Op-amp Input Stabilization System <talk>

Misleading the Op-amp of a Negative Feedback Circuit (introducing the positive feedback phenomenon) <talk> <group 64a>

Converting the Op-amp Non-Inverting Amplifier into an Op-amp Inverting Schmitt Trigger <talk> <group 68a>

Endowing a Transistor Switch with Memory (shows how to make a flip-flop) <talk> <group 67b>

How to Compensate Resistive Losses by a Parallel Connected Negative Resistor (reinventing the famous NIC) <talk>

Reinventing the Famous Deboo Integrator (shows the evolution of a passive RC circuit into a perfect active one) <talk>

Investigating the Bistable Mode of Negative Impedance Converters with Current Inversion

Demystifying gyrator circuits

Relaxation versus LC Oscillators (comparison between the two kinds of creating oscillations) <talk>

Ring oscillators: yet another way of creating oscillations

Common Circuit Questions (a list of questions, for which we need answers to understand, improve and invent circuits)

Op-amp Inverting RC Integrator reveals the secret of the legendary circuit

Table of contents [ edit ]

(contains a total of 184 titles of circuit stories)

ORGANIZING THE BOOK

CREATING A CIRCUIT METHODOLOGY

Revealing Circuit Ideas

Heuristic Tools

Using Analogies to Handle Circuits Using Analogies to Handle Circuits (scrutinizing famous pneumatic, hydraulic, mechanic, thermal and other analogies)

Visualizing Invisible Electric Attributes How to Visualize Invisible Electric Attributes (introducing voltage bars, voltage diagrams and current loops) Using Superimposed IV Curves to Visualize the Circuit Operation

Carrying out Unusual Experiments Imaginery Experiments (on a whiteboard, mental, etc.) Carrying out "Man-Controlled" Experiments (a man acting as a transistor, op-amp, etc.) Why Old-Fashioned Meters Are Better than VOM for Educational Purposes (needle versus digit) Slow the Process Speed to Observe the Circuit Phenomena (using an integrator instead an op-amp) <talk> "Living" Analogies (a computer simulated analogy synchronized with a real circuit arrangement)

Creative Thinking Techniques

How to Induce Creativity (collection of creative thinking techniques) How to Move Ideas from Mind's Eye to a Solid State Recorder (practical tips about idea recording technique) How Famous Circuit Inventors were Thinking when Inventing Why Creative Persons are Unhappy (why "normal" people treat creative persons badly) <talk>

REVEALING CIRCUIT IDEAS

Building the Simplest Electric Circuit (introducing the electrical phenomenon by non-electrical means)

Transforming Energy by Passive Circuits

Making Resistors Convert

Voltage Causes Current What is a Voltage Source? (unusual negative feedback viewpoint at the classical voltage source) Passive Voltage-to-Current Converter (extracted from the famous voltage-supplied Ohm's circuit) Passive Voltage-to-Current Converter (Circuit Fantasia story) Passive Resistance-to-Current Converter (varying resistance as an input variable) Passive Voltage-by-Current Divider (varying both voltage and resistance as input variables)

Current Causes Voltage What is a Current Source? (unusual negative feedback viewpoint at the classical current source) Passive Current-to-Voltage Converter (using a current-supplied Ohm's circuit) Building Current-to-Voltage Summer (applying Kirchhoff's Current Law) Passive Resistance-to-Voltage Converter (varying resistance as an input variable) Passive Current-by-Resistance Multiplier (varying both current and resistance as input variables)