Hi NicMac,
Try using a larger 'step' (i.e. 0.15 vs 0.1) to see if it helps smooth things out.
If you use USB interface,You need to install the 'PL2303_Prolific_DriverInstaller_v1.5.0.exe‘ first,
After install the USB drivers,then connect them with USB wire, and run software 'ads7871_v3s.exe', and select menu 'Options->Config',click the 'Auto Detect & Get parameter', if Curve tracer is connencted,then will diaplay a 'Parameter get from the device',otherwise,will display 'Device not online'.
After install the USB drivers,then connect them with USB wire, and run software 'ads7871_v3s.exe', and select menu 'Options->Config',click the 'Auto Detect & Get parameter', if Curve tracer is connencted,then will diaplay a 'Parameter get from the device',otherwise,will display 'Device not online'.
yeah that it is.
Got about 600 more then start again bin by bin
Then 1000 PNP
Then again fine sorting before they get soldered
No problemo boards not due in for couple of weeks
I am running curves and then taking HFE at one off fixed voltagge.
It would be great help is there was a curve number label on charth graph to make it easier to recognize instead to have to Hi light one by one.
Attachments
Got the labeling part down pretty good. Need to learn how to sort in excel. Could do it with progrgam I guess, but a streamlined process would be nice. Going to be trying some things this weekend with sorting. Bet LockyZ sort feature would be nice hint. OTOH, when you get em from the factory, they tend to stay nice and tight anyway
I have been able to get my fets pretty hot by using .01V step up. Dont know if others have experienced this Right now settled at .1V, but thinking of more dtatpoints for more accuracy. I wish there was a way to pick Vgs measurement points. THen you got primo control. Anyway, LockyZ, dont listen to me. I just fussing ove a phenominal piece of equipment.
I have been able to get my fets pretty hot by using .01V step up. Dont know if others have experienced this Right now settled at .1V, but thinking of more dtatpoints for more accuracy. I wish there was a way to pick Vgs measurement points. THen you got primo control. Anyway, LockyZ, dont listen to me. I just fussing ove a phenominal piece of equipment.
The device heating is proportional to the number of measurements points and the numbers of measurements at each point. I was actually thinking to use this effect to heat the device to operating temperature, but the software is not flexible enough to implement it well.
Importantly, you should decide the settings before doing the lot and not change them underway. The absolute values you get out are very settings dependent because of the device temperature.
I agree completely. Balance between too much heat and too few data points. Too much heat is clearly a bigger problem, so not too much of a decision. I pretty comfortable with the measurement setup, as it corresponds well to pre matched test. Any excel sorting experience you would like to share. Been too long and have forgotten too much. Use to be able to do about anything right out of school. Oh well.
No. I guess the problem is restricted to high current measurements and that the tracer is simply not up to the job without more serious hardware modifications.
Do you see the same thing? I may simply have a bad unit.
I did check the Ve columns:
For N-channel Ve is monotonically increasing.
For P-channel devices there are random changes.
So I'm probably experiencing both voltage drop and oscillation problems.
I do not have LM358 and/or TIP132/TIP137 replacement parts so nothing to do for the moment I guess.
For N-channel Ve is monotonically increasing.
For P-channel devices there are random changes.
So I'm probably experiencing both voltage drop and oscillation problems.
I do not have LM358 and/or TIP132/TIP137 replacement parts so nothing to do for the moment I guess.
Yes, Mine is doing it as well. Ill try replacing components. I think it also is related to max current capability, because yours begins at higher currents than mine.(I assume because you have increased current limit) Also, Mine seems to be related to frequency of the voltage steps in specified range. If i back off the number of steps, the oscillations/limiting start at a higher bias. All in all, though, fantastic piece of euipment that has shown be enormous accuracy. I retested some fets the old way under controlled temp/voltage/current conditions and the results match up extremely well.
They all discussed the V3 version of the software,It use USB interface with PC.
The link DIY Curve Tracer for PC is V2 version.
V2 version communication to pc with parallel printer port .V2 version has been terminated two years ago.
Exchanging does not help anything. From post #112 I actually understood that this/these op-amps only control the relays.
The problem persist and is highly reproducible preventing measurement of P-channel devices @ > 2.4-2.6A.
What do I try next?
NicMac,Locky Z
Mine is directly related to the frequency of the step up. If i back off on number problem goes away. Ill post a graph showing same fet under same circumstances with only difference being number of steps.
Shown is P channel under exact conditions, with the exception of V-Step being changed from .25V to .15V, and then to .1V
Mine is directly related to the frequency of the step up. If i back off on number problem goes away. Ill post a graph showing same fet under same circumstances with only difference being number of steps.
Shown is P channel under exact conditions, with the exception of V-Step being changed from .25V to .15V, and then to .1V
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