Transistor Checking

[Electro Fan]

I don't measure transistors often but when I do I'd like to get it right
Actually, I'd be happy to just get some consistent results, or different results I could explain.
Anyone have any ideas on why the results shown below might be different on the hFE?
Same transistor used for all the tests, of course.
I didn't have a fifth device to break the tie
Thanks

[Electro Fan]

After reading a Peak manual, maybe the Peak (and each tester device) uses a different collector test current and a different CE voltage and therefore the tests being run aren't really apples to apples for hFE?  In fact, Peak might use a collector test current of 2.5 mA for the DCA55 and 5.0 mA for the DCA75?  Kinda strange and potentially confusing.

So what these devices are showing are really just data points based on a set of  fixed inputs that can differ from device to device, so it's really a nearly random glimpse of a larger picture?  I guess on a larger Tektronix transistor checker the user could set test parameters and then look at curves, and here we have no control of test parameters and we get a data point instead of curves?

[Doctorandus_P]

Hfe is neither a tightly controlled, nor a constant parameter for a transistor.
Hfe changes with base current, collector voltage ("early effect") and probably also (a little bit) with temperature (touching it to insert it), moon phases and planet alignment.

The Atlas shows a higher base-emitter voltage, which strongly suggests a higher base current (A diode drop is also not a constant 600mV, but varies depending on the current). And with a higher base current, Hfe usually gets less.

Hfe also varies a lot during production. Variation now is probably less then it used to be, but some 40 years ago small signal transistors were sorted in the factory in three Hfe ranges: "A", "B", and "C". and then Hfe ranging from about 150 (Lowest for "A") to over 900 (Highest for "C"). If you want to learn to design reliable electronics, then you have to allow for such changes. "The Art of Electronics" has a few chapters about this topic.

[EPAIII]

In a well designed circuit it is the circuit that determines the gain, not the hfe of the transistor in it.

If you really need specific number for the hfe for your circuit to function properly, I would suggest you may need to redesign the circuit. I would. Or design a test circuit that measures the hfe under the circumstances in which it will perform in the circuit.

[liaifat85]

Here is a similar discussion I found: https://www.reddit.com/r/AskElectronics/comments/hz40hm/3_dmms_3_different_hfe_readings_same_transistor/