poynt99's Testing of Rose's Circuit 2013-06

Started by poynt99, 2013.06.22, 16:13:52

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Print
Go Down Pages1 2
User actions

poynt99

2013.06.22, 16:13:52 Last Edit: 2013.06.22, 17:40:07 by poynt99
First test will be conducted to establish the polarity of Pbat for the condition where the battery energy is depleting. Once known, we will have a baseline to compare against our measurements on the actual circuit.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99

#1
2013.06.22, 22:53:51
DSO Limitations

While taking some measurements I noticed that the "mean" of any trace will have a slight variance in value depending on where it is placed vertically on the scope screen. The degree of variance is enough to be of a concern, so I made a video illustrating this particular limitation one should be aware of when using DSO's. I've also outlined a method to virtually eliminate this slight flaw and get the most out of your critical measurements. Tektronix gives you the ability to add an offset to any trace, and doing so seems to eliminate this measurement artifact. I am not certain if Lecroy or Agilent, or any other DSO brands have this feature.

I will be utilizing this method whenever I can in the upcoming measurements.

The video will follow shortly.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99

#2
2013.06.22, 23:46:20
Here's that video demonstrating the variance of the mean measurement value on a trace as it transitions from bottom to top of the screen. Assigning a counter-DC offset to the trace seems to correct this scope artifact.

"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99

#3
2013.06.23, 00:12:42
This video demonstrates the use of a simple DC circuit to establish the polarity of the battery power measurement as per the connections on the schematic. In this case the polarity is POSITIVE. This circuit of course exhibits a battery whose energy is DEPLETING.

As such for the tests which will follow, a battery power measurement that is positive will indicate that energy is being depleted in the battery, and a measurement that is negative will indicate that the energy is being increased in the battery.

"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#4
2013.06.23, 07:33:30
Poynt
I must say that i don't know why the simple test hasn't been carried out on Rose's circuit. This is so easy even she could do it. No scope's or fancy equipment required-just a plain old DC volt meter of any description,and nothing more.
Test as follows.
Place volt meter across battery.
Run circuit for 10 minutes.
Disconnect circuit from battery
If battery voltage rises,then you were drawing more than you were returning to the battery.
If battery voltage drop's,then you were returning more than you were drawing from the battery.

When you charge an SLA and disconnect the charger,the voltage will always drop to a rest voltage. When you draw from an SLA,the voltage will always rise to a rest voltage when the load is removed. I am yet to see any device that shows otherwise when it comes's to SLA's.
This is going on your comment
Quote: As such for the tests which will follow, a battery power measurement that is positive will indicate that energy is being depleted in the battery, and a measurement that is negative will indicate that the energy is being increased in the battery.

But i was under the understanding that her circuit wasn't so much a loop circuit,but able to dissipate more heat energy than watts of power from the batteries to do so?. In this case,the test above is no good to use. The test above is for the loop system's where people claim to be charging the supply battery faster than it's being depleted.
Never let your schooling get in the way of your education.

poynt99

#5
2013.06.23, 14:18:00
tinman,

You are absolutely correct about the battery voltages after running the circuit. It would most certainly tell you if the battery energy was depleting or increasing before you disconnected the circuit. Maybe Rose has already noticed this, maybe not. I doubt she would admit it.

In terms of the circuit and test I posted above, that has little to do with RA's circuit actually. It is presented ONLY to determine the polarity of a battery power measurement with the given probe configuration. And since it is easy to determine this when the battery is depleting, that is what was done. The same probe configuration will be used on the RA circuit, so we can carry forward the rule we established with this simple circuit.

Hope that makes sense.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#6
2013.06.23, 15:16:55
It make's a lot of sence,but what is this about the DMM's,and people doubting what about them?
Never let your schooling get in the way of your education.

poynt99

#7
2013.06.23, 17:12:04
Quote from: tinman on 2013.06.23, 15:16:55
It make's a lot of sence,but what is this about the DMM's,and people doubting what about them?

The doubts are whether two DMM's can be used to obtain an accurate Pbat measurement with oscillating/switching circuits such as RA's.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

poynt99

#8
2013.06.23, 17:29:26 Last Edit: 2013.06.23, 18:58:36 by poynt99
Attached is a drawing of the circuit I'll be testing with added protection and CSR components.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#9
2013.06.23, 23:23:08
Quote from: poynt99 on 2013.06.23, 17:12:04
The doubts are whether two DMM's can be used to obtain an accurate Pbat measurement with oscillating/switching circuits such as RA's.
Well up until a couple of days ago, i would have been one that believed they could.I have always relied on my DMM's for P/in , but now i will have to be a little more careful i believe. That new device i am messing around with (the dovada transformer) was the first time i couldn't get an accurate P/in with my DMM's. What made this apparent was the DMM reading I/in went to a negative value. Apon adding a large cap between the device and DMM, the DMM then went back to a positive value-and we are only talking about a 90mA draw @ 12 volts here, with the DMM set on the amp scale. First time i had ever seen that(the DMM go negative),so now i will be taking a little more care with DMM's and pulsed circuit's.
Never let your schooling get in the way of your education.

poynt99

#10
2013.06.24, 13:44:52
tinman,

I'd be interested in seeing the circuit you were measuring with your DMM's, and where the measurement points are. I want examples I can try so as to determine if the method is fool-proof or not.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#11
2013.06.24, 14:20:20
Quote from: poynt99 on 2013.06.24, 13:44:52
tinman,

I'd be interested in seeing the circuit you were measuring with your DMM's, and where the measurement points are. I want examples I can try so as to determine if the method is fool-proof or not.
Hi Poynt
What i did was wound another coil around the dovada transformer, using fine copper wire. This was to get away from using the FG to drive it,so as i could eliminate any power coming in from the FG. I just used the berdini ss/ssg circuit to run it and see what happened. The DMM (for I) was between the power supply and primary coil. All was good until i hit one spot on the 1k pot when tuning. The DMM then started reading a negative current. Now a year ago,i might have started to get excited,but now i know better. So i placed a large cap(10 000uF) between the coil input and the DMM,and negative of the cap to common ground.The DMM then started reading a positive current draw again. The odd thing was,the power supply always read a positive current flow,even when the DMM was reading a negative current flow. I believe the reason the power supply kept reading correctly is because it has large smoothing caps on the output.
First time i have seen my DMM's swing to a negative current though.

If you like, i can throw a video together showing this happening,and then add the cap,and show the DMM read correctly again. But the circuit was just the ss/ssg-nothing more.
Never let your schooling get in the way of your education.

poynt99

#12
2013.06.24, 15:05:56
So you were pulsing a primary coil with your FG, and the DMM was in series with the FG?

If so, that would explain it. The Pbat measurement I am referring to is with a battery, i.e. constant DC voltage.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#13
2013.06.24, 22:46:58
Quote from: poynt99 on 2013.06.24, 15:05:56
So you were pulsing a primary coil with your FG, and the DMM was in series with the FG?

If so, that would explain it. The Pbat measurement I am referring to is with a battery, i.e. constant DC voltage.
No-as stated above,the DMM was between the power supply and the primary coil-no FG in the circuit. The secondary coil i wound over the top of the primary was only to trigger the transistor. The power supply was reading a positive current,and the DMM was reading a negative current until i placed a cap between the primary and DMM.
Never let your schooling get in the way of your education.

poynt99

#14
2013.06.24, 23:26:40
Sounds like you need to draw it out. I think there may be more going on and I don't want to guess.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#15
2013.06.27, 00:47:30
Quote from: poynt99 on 2013.06.24, 23:26:40
Sounds like you need to draw it out. I think there may be more going on and I don't want to guess.
Hi Poynt
It seems that it may be an effect only with the benchtop power supply,as when i use batteries,there is no reverse current detected by the DMM. So with batteries,it seems the DMM's read correctly-but with the power supply they can read wrong. This may be because of the capacitors within the power supply being on the wrong side of the meter? ,as when i put a cap between the DMM and load,the DMM reads correctly again while using the power supply.
Never let your schooling get in the way of your education.

poynt99

#16
2013.06.27, 01:00:17
Could be Brad. I'm just not sure I understand what you are doing exactly?  :D
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#17
2013.06.27, 08:06:00
Quote from: poynt99 on 2013.06.27, 01:00:17
Could be Brad. I'm just not sure I understand what you are doing exactly?  :D
Hi Darren
It is just a simple circuit as drawn below,sory for not posting the schematic sooner.
So in this case using the bench top power supply gives me a negative current reading on the DMM,but using a battery as our power supply gives me a positive current reading on the DMM.
I am glad i found this,as i will have to be carful using the power supply for P/in when taking measurement's. I will now make it a habbit to place a cap after the DMM to make sure it's reading correctly.
Never let your schooling get in the way of your education.

poynt99

#18
2013.06.27, 13:19:04
Brad,

Thanks for the diagram. I would try placing the caps directly across the PSU. The PSU output impedance may be high, and connecting some caps there will effectively lower it.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#19
2013.06.28, 16:02:34
Hi Poynt
How is this testing comeing along?.
Never let your schooling get in the way of your education.

poynt99

#20
2013.06.28, 18:51:38
It's coming OK. Trying to be thorough and comprehensive, so taking my time.

I'm also eager to see how the demo goes tomorrow morning ;)

Stay tuned for more results.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#21
2013.06.29, 00:53:59
Do you have the link where we can watch this demo?
Never let your schooling get in the way of your education.

poynt99

#22
2013.06.29, 03:35:16
Brad, I could only find this on Mark's website.

Somehow I got an invite.
"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." Frank Zappa

TinMan

#23
2013.06.29, 10:10:00
Well dont hold your breath Poynt

Quote Rose; The team member doing the demo is away in Namibia until Saturday morning.  So we're cutting a fine line for the demo and it may be as well to delay this until our time 18.00 hours - 6.00 pm.  But I'll check with him.  But he'll most CERTAINLY guide you in how to get this setting.  I'll post the time on WEDNESDAY - as I undertook - and when I've had some feed back.  The downside of the 6.00 time is that it's dark here by then - as we're in mid winter.  And my study is not really that well lit.  But we could do the demo in the living room.  Anyway.  That's a detail.

Seems like this is a leadup excuse in the making for another bail out on the demo.
I'll give 8:1 odds on it.
Never let your schooling get in the way of your education.

TinMan

#24
2013.06.29, 16:25:47
Just a couple of scope shots looking at how a power transistor fired circuit looks,insted of using mosfets.
Never let your schooling get in the way of your education.
Print
Go Up Pages1 2
User actions