RANT CAFFE ASYLUM

[EMJunkie]

Have you looked at the scope shots?  There appears to be all kinds of high frequency harmonics and "hash" scattered all over the screen.

If you want to know the frequency content of your waveforms, look up the spectrum/FFT function on the scope and give it a try.

That little box with a frequency readout on the scope does not tell you the frequency content of the observed waveform (unless its a pure sine wave).

PW

How about you give it a try?

Its not hard, or expensive! Metal Strip 0.1 ohm 1% falls in the category of a Precision Resistor, I guess some are not that smart to understand this?

EMJ

[picowatt]

How about you give it a try?

Its not hard, or expensive! Metal Strip 0.1 ohm 1% falls in the category of a precision Resistor, I guess some are not that smart to understand this?

EMJ

The example I used was relevant to your 0.1 ohm resistor.  The inductance of your CSR, as connected, will be very close to 10nHy.  At 1.7MHz it will appear to be 0.2 ohms, a 100% error.  It gets worse with higher frequencies.

Using a similar 1 ohm resistor would reduce that 100% error to 10% at the same frequency (and as above, get worse at higher frequencies).

As Onepower stated "... a DSO is only as good as the person who knows how to operate it, knows it's limitations and knows what there measuring and seeing."

Just about everything related to sources of measurement error has been discussed ad nauseum in older threads.

PW
 

[EMJunkie]

The example I used was relevant to your 0.1 ohm resistor.  The inductance of your CSR, as connected, will be very close to 10nHy.  At 1.7MHz it will appear to be 0.2 ohms, a 100% error.  It gets worse with higher frequencies.

Using a similar 1 ohm resistor would reduce that 100% error to 10% at the same frequency (and as above, get worse at higher frequencies).

As Onepower stated "... a DSO is only as good as the person who knows how to operate it, knows it's limitations and knows what there measuring and seeing."

Just about everything related to sources of measurement error has been discussed ad nauseum in older threads.

PW

Why do you keep presenting Fake Data? I told you, 1.7 MHz is no where near the frequency we are using! We are well under 1 MHz! One was 3KHz!

Information provided by onepower has been proven wrong many many times, I cant trust someone that presents data that is incorrect!

EMJ

[onepower]

picowatt

Have you looked at the scope shots?  There appears to be all kinds of high frequency harmonics and "hash" scattered all over the screen.
If you want to know the frequency content of your waveforms, look up the spectrum/FFT function on the scope and give it a try.
That little box with a frequency readout on the scope does not tell you the frequency content of the observed waveform (unless its a pure sine wave).

I think you get it, in fact the frequency was over of 987kHZ in the video near 1 MHZ. The maximum resolution of the DSO is 100 MHZ which means the resolution of the data is 100 to 1 at best with respect to which part of the signal it was triggered by or locked on to. Obviously it's a very complex signal with a great deal of hash so did it average part or the whole of the higher frequencies present?.

Here's a hint, whenever any value of the DSO, in all the values displayed starts reading null values the computer doesn't like what your doing like in the video. It does not compute, more so when a given period of one frequency rapidly changes to another frequency which not only introduces phase angles but interference as frequencies riding on other frequencies. Another hint, having programmed computers since they were invented I know computers are not smart but stupid. The logic and reasoning are only as good as the person who programmed them and we are far from perfect. Thus every computer is just waiting for an instance which we could not foresee that it cannot compute.

So wishful thinking is wonderful, I do it all the time, however reality is very hard and we should make the effort to understand what it is we think we are doing or seeing. As I said, this video is a joke and I would be embarrassed to show it to anyone I consider rational or a professional. They would tear it apart asking questions of the person who made it look stupid and has no answers for. Thus if your going to do it... do it right.

Regards

[picowatt]

I told you, 1.7 MHz is no where near the frequency we are using! We are well under 1 MHz!

Do you not see all sorts of high frequency hash on Captainloz's waveforms? 

Just because the scope has a "frequency" readout, that readout is not telling you what the "frequency content" of the waveform is (except for a pure sine wave).

Inductance in the CSR is only one possible source of error, and common sense should tell you there must indeed be measurement errors.

Why? Because it does not take 17 watts to light a pair of 2.8 watt lamps...

PW