Claimed OU circuit of Rosemary Ainslie

[WilbyInebriated]

The post was to comment on the inductance in the ground leads of a single-ended scope probe. I also tested a few other ground leads and they came out to read in the same range as what I posted. It's safe to say then, that these are typical values for a scope ground lead.

what you meant to say of course was, it's safe to say then, using my meter, that these are typical values for a scope ground lead.

[poynt99]

From United States patent:

Low inductance ground lead
United States Patent 4838802

A common problem in the measurement of high frequency signals is that the self-inductance of the ground connection to the signal probe combines with the input capacitance of the signal probe to form a series resonant circuit that not only reduces the amplitude of the input signal with increasing frequency, but produces ringing. This increasingly degrades the accuracy of the measurement system with increasing signal frequency. Typically, the ground connection to a signal probe comprises a ground lead made of braided wire, and a ground probe to which the ground lead is connected, both of which have relatively high self-inductances.

The capacitance of typical signal probes in use for high frequency measurements is on the order of 10-15 picofarads. The self-inductance of the signal probe from the signal source to the point of contact with the ground lead, the inductance of the ground lead, and the self-inductance of the ground probe (which is the means of completing the circuit to ground) from the point of contact with the ground lead to ground all contribute to the inductance of the signal path. However, the inductance of the ground lead is the primary contributor to the total inductance in the signal path.

The inductance of conventional ground leads is on the order of 200-300 nanohenries.

300nH = 0.3uH

I'd say my meter is providing an accurate inductance measurement.

.99

[poynt99]

The inductive reactance of a 0.35uH inductor (a typical 6" ground lead) at 7MHz is over 15 Ohms.

.99

[WilbyInebriated]

From United States patent:

Low inductance ground lead
United States Patent 4838802

300nH = 0.3uH

I'd say my meter is providing an accurate inductance measurement.

.99

i didn't say it wasn't. i just wanted to point out how you leave out little subtleties in what you should be saying vrs. what you say. like your argument about your simulations...

i thought you were ignoring me? but i like your circular argument... can you post us a picture/video of your fancy meter actually making said measurements?

[fuzzytomcat]

The oscilloscope shots appear unchanged for the most part. An indication that Fuzzy's previous shunt resistor inductance itself may not have been contributing substantially to the skewed current/voltage phasing.

However, since a single-ended probe (assumed) is still being used, there is the ground lead still at issue, and I am somewhat curious where the ground lead is being connected; to the negative side of the shunt (assumed), or some AC ground point?

The probe location for the battery voltage should be indicated.  Where is the ground lead for this probe located?

A photo of the test setup would be appreciated, showing where the battery is and where the scope probes and their associated ground leads are located.

Any temperature readings, CONTROL tests etc? Or was this test simply to compare the shunt resistors?

.99

Here are the photos you wanted and all I have time for at this point, Harvey is working on a illustration of the set up with all the wire sizes and lengths and possibly will appear when he has finalized it in this forum. This is getting a little old when you are always "COMPAIRING" my publicly posted complete results with your mystery results and setup mostly only "SPICE" simulations and the obvious problems you must have using a dual channel power supply and not battery's or ground loops or a combination of both.

The last testing was the results of TEST #8 ( old shunt resistor) and TEST #9 ( new shunt resistor) and the comparison between images and data the different "SHUNT" resistors may induce in the circuit as indicated in the postings.

Temperature readings during this"SHORT" test .....

Ambient Temperature - 77.6 F
Load Resistor Temperature - 134 F
Shunt Temperature - 110 F
Mosfet Temperature - 164 F
555 Temperature - 123 F

Fuzzy