Weekly updated columns:  questions - paradoxes - contradictions - conflicts - principles - building schemes

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Every week I add here a little story about paradoxical circuit phenomena in mystery circuits. I number and date these ideas consecutively as they have appeared in my mind; then, I arrange the paradoxes systematically in order of circuit evolution - passive > transistor > op-amp etc. Browse through the list below or just click Current Paradox to find the week's paradox.

I began implementing this column a year ago as a flash movies; after I had created the first nine paradoxes I temporarily stopped the column. If you want to view these flash versions, click the fuchsia colored paradoxes.

In order to know more about the topic discussed, copy the paradox name from the table below, paste it in the subject field, add additional questions in the message body and e-mail me. Your e-mail will not be automatically answered; I will prepare every e-mail answer especially for you revealing the circuit strangeness in a catchy and exciting manner. Thus you will get unusual and original explanations of the circuit properties that you have never seen before!

The circuits from this page are also presented in the constant e-mail circuit columns circuits, questions, paradoxes, lessons and in the weekly updated circuit columns questions (flash animated), contradictions, conflicts, principles, building schemes. Browse through these pages and ask questions!

November 08, 2004

Voltage source versus current source The good voltage source is a bad current source and v.v., the good current source is a bad voltage source. Why?

November 15, 2004

Voltage source versus load In many electronic circuits voltage sources act as loads and v.v. sometimes loads act as voltage sources. What are these circuits? How do you explain these paradoxes?

November 22, 2004

Current source versus load In some electronic circuits current sources act as loads and v.v. sometimes loads act as current sources. What are these circuits? How do you explain these paradoxes?

November 29, 2004

Perfect voltage source versus real one

In some electronic circuits good voltage sources act as bad ones and v.v. sometimes bad voltage sources act as good ones. What are these circuits? How do you explain these paradoxes?

December 06, 2004

Perfect current source versus real one

In some electronic circuits good current sources act as bad ones and v.v. sometimes bad current sources act as good ones. What are these circuits? How do you explain these paradoxes?

December 13, 2004

Sometimes bad voltage source is desired Most of the car alarm systems include the so called current sensing. In this case, a paradox appears: the worse the car battery is, the better the alarm system works. Why?

December 20, 2004

Conductor versus resistor In some electronic circuits conductors act as resistors and v.v. sometimes resistors act as conductors. What are these circuits? How do you explain these paradoxes?

December 27, 2004

Ideal voltage load An ideal voltage load is ... nothing?! But yet, what is it? Compare with an ideal current load!.

January 03, 2005

Ideal current load An ideal current load is almost... nothing. But yet, what is it? Compare with an ideal voltage load!

January 10, 2005

Passive Elements: Resistors, Capacitors, Inductors

January 17, 2005

Resistors and energy Resistors are harmful as they dissipate energy; but yet we use them in electronic circuits. Why? How do we explain this paradox?

January 24, 2005

Capacitors and AC current A nonconducting dielectric material is placed between the plates of the capacitor; but yet it passes AC current. How do we explain this paradox?

January 31, 2005

Inductors and AC current A conducting wire is connected between the leads of the inductor; but yet it stops AC current. How do we explain this paradox?

Passive Circuits (Converters)

February 07, 2005

Simple current source In order to reduce the obstacle introduced by the nonideal current load connected to the simple current source we ... introduce and even increase another obstacle?!? How do you explain this paradox?

February 14, 2005

Capacitive integrator Resistors are harmful as they dissipate energy; but in order to reduce the error in the circuit of a passive capacitive integrator we ... even increase their resistance?!? How do you explain this paradox?

February 21, 2005

Potentiometer A voltmeter measures voltage, an ammeter measures current, a potentiometer measuses ... nothing!? Once it is not a meter why do we say a potentiometer? How do we explain this paradox?
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Amplification

December 22, 2003

Transistor amplifier A transistor does not amplify; it just ... attenuates!
A transistor is not an amplifier; it is an ... attenuator!
Why?

December 29, 2003

Op-amp amplifier An op-amp does not amplify; it just ... attenuates!
An op-amp is not an amplifier; it is an ... attenuator!
Why?

January 05, 2004

Amplifier Amplifiers do not amplify; they just ... attenuate!
An amplification does not exist! It is just ... an attenuation!
What do you think? Why?

February 28, 2005

Regulating element A non-linear regulating element (e.g. a transistor acting as a current stable element) provides ... linear regulation ?!? How do we explain this paradox?
Interacting Voltage Sources (Potential Conflicts)

January 12, 2004

Capacitive differentiator There is something incorrect in a capacitive differentiator...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

November 10, 2003

Diode peak detector There is something incorrect in a diode peak detector...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

November 17, 2003

Sample & hold circuit There is something incorrect in a sample & hold circuit...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

November 24, 2003

Common-base amplifier There is something incorrect in a common-base amplifier...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

December 01, 2003

Emitter-coupled amplifier There is something incorrect in an emitter coupled amplifier...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

December 08, 2003

Transistor differential amplifier There is something very incorrect in a transistor differential amplifier...
What is the paradox of this popular electronic circuit?
Hint: What does a voltage source "like"? What does it "hate"?

September 27, 2004

Parallel connected voltage sources (generalization) In general, there is something very incorrect in a circuit consisting of parallel connected voltage sources... What is the paradox of this connection? Is it wrong? Is it useful? May we apply this connection into practice?
Interacting Current Sources (Current Conflicts)

October 04, 2004

Inductive differentiator There is something incorrect in an inductive differentiator...
What is the paradox of this popular electronic circuit?
Hint: What does a current source "like"? What does it "hate"?

October 11, 2004

Transistor amplifier with dynamic load There is something incorrect in a transistor amplifier with dynamic load...
What is the paradox of this popular electronic circuit?
Hint: What does a current source "like"? What does it "hate"?

October 18, 2004

Transistor amplifier with dynamic load controlled There is something very incorrect in a transistor amplifier with dynamic load controlled... What is the paradox of this popular electronic circuit?
Hint: What does a current source "like"? What does it "hate"?

October 25, 2004

CMOS inverter There is something very incorrect in a CMOS inverter...
What is the paradox of this popular electronic circuit?
Hint: What does a current source "like"? What does it "hate"?

November 01, 2004

Series connected current sources (generalization) In general, there is something very incorrect in a circuit consisting of series connected current sources... What is the paradox of this connection? Is it wrong? Is it useful? May we apply this connection into practice?

Transistor Circuits

March 07, 2005

Common-base amplifier A common-base amplifier is just a reversed common-collector amplifier (emitter follover)?!? How do we explain this paradox?
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Send the e-mail to cyril@circuit-fantasia.com.

Last updated March 8, 2005