Last time I did only some very basic tests with the Peak Electronics DCA75+ component tester. Some weeks ago, I wrote that I bought some special transistors along with other stuff. I took this as a good occasion to see what this thing can really do.
I used the BFX81 'high speed complementary amplifier' as test specimen. As I got two of those, I ran some tests comparing 1 vs. 2 as well as npn vs. pnp. As can be seen from the examples, the problem with the crowded diagram areas intensifies for some graphs. The procedure using the PC software is straightforward and quite flexible. If you save the diagram data for each graph (and remember to give them a properly identifiable name), you can call up saved data into a newly measured graph or even recreate the graphical display from two sets of saved data.
There is one difference although. When subsequently measuring two sets of parameters into one graph window, the two curve sets are assigned different colours. When you measure them independently, they will have the same colours. The colour as well as the label of any individual curve can be set in advance or changed later - also for curves resulting from saved data. The overlapping of the labels is unfortunately something that can't be corrected.
For these tests, I did not modify the parameters yet. This could help a bit, as noted earlier. Next, I'm going to try that and I also want to try what Excel can acieve with the data sets. Until now, I have only checked that they can be inserted from the curve display as shown in the manual. Importing the stored data directly is more complicated, as they are stored in a .txt file with ancillary information so that defining an import conversion will take some work.
See the examples:
(NPN 1vs2 hfe over Vce produces crowded, almost unreadable graph. NPN 1vs2 Ic over Vce is quite readable. NPN vs. PNP 1 hfe over Ic had me wondering a bit - I expected the NPN to come out better. Graph is usable and it was no measurement error. NPN vs. PNP Ic over Vce is interesting when compared with the NPN 1 vs. 2 graph. In the NPN vs. PNP Ic over Vbe it is not even possible to see all 10 curves, as they are partially overlapping each other. Also here the selection of the parameter range makes no sense. If I were interested in what happens below Vbe = 0.6V, I would not want it together with the 'working segment' in one diagram. For the normal part of this diagram, this could be cut off.)
Will be continued...
(part 1 found here:
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3530794/#msg3530794)