@Garrett: I hope you won't take this the wrong way, but it strikes me that you might be kind of easy to fool with a fake FE/OU device, if I don't let you do ad-lib measurements but restrict you in some way, like making you use AC coupling, or omitting a certain particular test.

Honest scientists are often the easiest people to fool, because they are trusting and they have strong preconceptions about what is happening. They have a tendency, as we all do, to focus on the Red Herring and not to consider possible alternative explanations for what they are seeing.

http://www.youtube.com/watch?v=1I6TlPjYIpE

 

I never did give my "def." as to what constituted "DC," simply as it would require calculus and integrals. Why, you might ask? Because we can still measure an "effective" DC level from pulses or random signals which statistically have a "bias" favoring one direction. DC can be reduced to a special case of AC. Integration is your friend in these instances. Which brings me to my next point. The "DC" setting on the scope lets everything through unfiltered. You would have to be pretty dense to think that it only lets "DC" signals through: as that would defeat the point of an amplitude vs time plotting machine--ideal DC, in theory, is in variant. So you know "who" your dealing with if they believe the shenanigans you've outlined. Which makes it hard for me to believe there is any significant number of people who could be as ignorant as you claim, which forces me think you're using logical fallacies. In this case either a false analogy (which was the LED argument for sure) or straw man argument.

As for my gullibility, indeed I am likely to actually listen to what someone says and carefully examine their work without prejudiced. Why? Because I'm not emotionally invested in maintaing a status quo of orthodoxy or have Super Man syndrome thinking I'm going to save the world with FE. I'm just a honest and curios dude who likes the subject of alternative science, but more so mainstream science. In particular I'm a working towards a double masters encompassing physics and chemistry in the hopes of becoming a "material scientist." Although I've always like playing around with electronics and building circuits particularly obscure things like home made transistors, plasma triodes, home brew photo detectors and the like. Another hobby involves repairing and collecting vintage test gear, particularly HP and Keithley equipment from the 80s (mainly because that's all I can afford--stuffs dirt cheap).

All that said, I do feel confident in my ability to scrutinize while at the same time being open and receptive to new ideas. Becoming dogmatic and indifferent doesn't sit well with me.

Quote from: TinselKoala on August 07, 2014, 02:07:24 AM
Here's an _old_ video I made concerning the issue of AC vs DC voltages. This was before I found a better video transcoder so I apologise for the poor video quality.
Using AC-coupling on the scope would take the offset signal, and move it down to the channel baseline, allowing you to display an LED that was ON even when the scope trace says it should be solidly off. Or many other interesting effects. So if you see AC coupling being used in a situation where the _vertical measurements_ are important, I strongly advise you to make the presenter tell you exactly why AC coupling is used and what effect it has on the measurements. Ask him to switch momentarily to DC-coupled... if you see a difference in the trace, you are getting snowed.

http://www.youtube.com/watch?v=jg2_yE5dEQg

Always has been a good question this one. But are we talking current or voltage TK ?,because as we know in some situations,a current can remain flowing in one direction,but the voltage polarity can change. So using your analogy in the video,there are some situations where we have a DC current,but an AC voltage-it gets all so confusing 

As far as current go's,it would depend on what you see as alternating. Is it AC when the current changes in amplitude,or in direction of flow?.If we are to go by Tesla,AC is the change in current flow direction. then in regards to voltage,well the opposite seems to apply. When we have say 12 volts DC,there is no alternating of the voltage-it is 12 volts DC.But if the voltage rises and falls between say 6 volts and 12 volt's,we then have an alternating voltage,although the voltage dosnt change polarity.

So i think you need to seperate the two(current and voltage),as there are situations where current can flow in one direction (DC),but voltage can change polarity.

On my forum,we came up with a solution,so as all there would know what we were talking about.
If we had a DC current that altinated in amplitude,we simply called it ADC (alternating direct current).

Garrett, you are engaging in a rather extreme degree of scholasticism, I think.

Are you seriously trying to get me to believe that you would do a power measurement on an unknown circuit using an AC-coupled oscilloscope? That is the point of my entire discussion.  I don't much care how you define your terms, I do care what your approach to measurement is going to be. I have illustrated a very simple case where the "real output" the brightness or power dissipation _by the bulb_ is much greater than you will measure on the scope as being supplied to the bulb, IF you use AC-coupled channels. Is this or is this not true? If you think that is some kind of "straw man" then I submit that I could indeed fool you with a black box device.

Now suppose you were confronted with the Black Box version of a more complicated circuit that is being demonstrated to produce excess dissipation in the load -- Kapanadze or Akula or Gmeast or Ainslie or such, and the evidence shown to you included data from AC-coupled scopes to tell you power and phase. Would you accept it, or not? Remember, you do not know the exact circuit so you have no rational basis for choosing one or the other coupling setting. Would you accept the AC coupled data or would you in fact want to see _all_ the power that is being supplied to the DUT?


@TinMan.... Alternating DC.... yah, that will be very helpful. Let me ask you something: Have I helped you at all in your understanding of oscilloscopes and their use? Have I led you wrong in any way, so far? Would YOU accept data from an AC-coupled scope in the situations I have described above?


Just for amusement purposes only:
http://www.youtube.com/watch?v=Frp03muquAo
http://www.youtube.com/watch?v=Pr3Olkd_5EI