Talk:Circuit Idea/How Does an Active Follower Behave when Disturbed?

Here is the building "scenario" that my students (group 64b) and I were using during Lab 3 to reveal the unique property of the series negative feedback circuits to overcome all kinds of disturbances. Circuit-fantasist (talk) 07:45, 28 April 2008 (UTC)

Is the real diode a perfect component?


A forward voltage drop VF appears across a real diode when a current flows through it... What is this voltage drop - useful or harmful? Sometimes it is useful; other times it is harmful...

"Useful" examples. When we make voltage stabilizers, we need this voltage drop. In these cases we do all that is possible to create and increase this useful voltage drop appearing across various diode component: diodes, LEDs, zeners, multiple diodes connected in series...

"Harmful" examples. In other cases, when we use a diode as a switching element, we do all that is possible to remove and to remove this harmful voltage drop... Then we need an ideal diode without forvard voltage drop VF...



Making the simplest series diode rectifier




Deriving the basic idea from our human routine
(write here all the situations in your daily routine where you have remove all the obstacles standing in your way:) Circuit-fantasist (talk) 07:33, 27 April 2008 (UTC)

Implementing the powerful idea into an electrical circuit


Making an almost ideal "op-amp" series diode rectifier
What can act as a varying voltage source in our electronic circuit? What can "help" the imperfect diode by adding so much voltage to the input voltage as it loses across the diode? At last Lab 3 we were using transistors for such a purpose; let's now, for the sake of change, use an op-amp...



Now the op-amp has to "insert" the "helping" voltage VF into the circuit; so, how to connect it?



Eureka! We have invented an (almost) ideal diode without (any) forvard voltage VF! Let's investigate it by Microlab system.



...multiple diode voltage drops...










...battery voltage...






...resistor voltage drop
With the same success we can overcome the "harmful" voltage drop across a resistor. What a circuit can we "invent" in this way? Write its name here.... (reifilpma gnitrevni-non:)



Application. Now look at the old fashioned laboratory power supply that has helped us to carry out the famous Ohm's experiment. In addition to the positive and negative terminals it has also two mystic terminals named NFB. What are they? Why and when do we need them? Describe here and draw a picture about a possible application of this arrangement. By the way, when I was student and then young engineer, I have managed to burn out a few costly microchips when I was trying to supply them:((( What do you think, how have I managed to do that "heroism"? Circuit-fantasist (talk) 08:25, 27 April 2008 (UTC)









Making the harmful voltage drop act as an input






Resources
Strange things can be put into feedback loop a cheerful animated story (after Tom Hayes's Student manual for the art of electronics).

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