Claimed OU circuit of Rosemary Ainslie

[poynt99]

Hi BEP,

In this circuit the MOSFET Drain Load is what we're referring to as the load resistor.

The resistor in the Source is the "shunt".

So I assume Hoppy had the probe on the V+ rail and the gnd clip on the Drain.

.99

[poynt99]

Yes, this is what I said in my post 929.

Hoppy

I know Hoppy

I was re-iterating/emphasizing it because it seemed TK may have missed that.

.99

[BEP]

Hi BEP,

In this circuit the MOSFET Drain Load is what we're referring to as the load resistor.

The resistor in the Source is the "shunt".

So I assume Hoppy had the probe on the V+ rail and the gnd clip on the Drain.

.99

Thanks. I must have missed that somewhere along the line. I assume this was done because the output of the 555 and the action of the MOSFET -ARE- reversed from the way RA and her clan understand it?

[poynt99]

To be honest BEP, I don't know what the RA clan understands and doesn't understand anymore.

For our own sake, I think it's best we use commonly-accepted terminology so at least we understand each other when we're discussing this circuit.

The 555 output is definitely not a 3.7% duty cycle, regardless of whether it is required or not, which still has not been fully clarified by the RA camp IMO, and the 555 circuit as published in the Quantum article certainly can not be adjusted lower than about 70% duty cycle despite any ignorant comment about it made by Mr. Mis-informed/misguided-- Harvey.

.99

[MileHigh]

Hoppy and Gang,

Like .99 said, if the scope probe is across the coil-resistor then the waveform looks fine, and in Hoppy's case it is very clean.  It's almost too clean looking but the real check for any inductance can be done at the shunt resistor.

There is not much point in putting the scope coupling on AC for this experiment, DC will do you just fine.  Will Aaron take that phrase and with his limited understanding try to turn it into another "MH doesn't not know what he is talking about" sleazy pitch to his audience of the converted?  Time will tell.

Rosemary's channel A measurement has always been bogus anyways and gives you no real information at all.  It just shows you how the battery is coping with the load.  Some "experts."

If you look at the shunt resistor waveform and barely notice the exponential rise in the current waveform for you normal MOSFET "on" time then indeed it would indicate there is very little inductance in your coil-resistor.  If you measure the total series resistance in the loop including the MOSFET when on, and up your scope time base to make your very narrow exponential curve more visible then you can calculate the inductance if you want to by eyeballing the 63% rise time.

To make a general comment:  When you are first exploring any circuit it is always preferable to use both traces on your scope at the same time ->  555 vs. shunt resistor, 555 vs. coil-resistor, etc.  I think of all of the text generated over things like the ring-down oscillation on the shunt resistor waveform.  Over and over the point was made that the MOSFET was off during the oscillation.  Just displaying the 555 trace next to the shunt resistor trace would have made that perfectly clear right away.  I still think that the ring-down was nothing more than the ringing in the wire itself.  That's a concept that Rosemary can't understand at all.

My minor pet peeve is that people almost never use both scope traces, when you gleam 10 times as much information with two channels as compared to a single channel.  My major pet peeve is when people do a clip and do not explicitly state at the beginning of the clip which two points that they are measuring across.  I suppose that everyone assumes that the ground of the scope channel is on the ground of the circuit but in fact it could be anywhere.  Often people make clips and don't even say where the scope probe is connected in the circuit at all!  Rant off.

MileHigh