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Measuring hfe of a transistor by multimeter ?
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Neilm:

--- Quote from: tom66 on April 18, 2015, 11:02:42 pm ---One of the main reasons meters have stopped including the transistor tester is it prevents them getting any kind of  safety certification.

--- End quote ---
Technically no - they can get safety certification, the tester just needs to be isolated from the input jacks.
smjcuk:
My dinky little Uni-T UT33A has no conduction path to the probe ports and the transistor tester pins by the looks.

Transistor hfe tester is very useful even if its not accurate. If you've partially buggered, toasted, zapped, vaped or otherwise mutilated a transistor then the hfe can drop to 1/5 of its colleages' value (transistor pain = less gain). Its also good for spotting naff ones shipped by the hundred from aliexpress.

I got through 5 of them building a current source the other week. Sort of 'oh that one is a bit hot', hfe check, hmmm 10 instead of ~200 trip to bin, get a new one out.

LTspice is probably cheaper so I don't recommend my design methodology :)
paulvo:
It is very interesting to put a transistor in a simple test configuration using 3 resistors and an adjustable power supply, and measure simultaneously the collector current and the base current.
For a BC547, you can use a Rc=2K7, Rb=390K and Re=56ohms.
When you vary the base current from 10µA -> 20µA -> 30µA -> 40µA -> 50µA by increasing the supply voltage, note down each time the corresponding collector current.
Then for these various values, divide de collector current value by the base current value, to obtain the hFE
You will find that hFE will vary with the collector current (as was already stated by XFDDesign).

In addition, I measured the hFE using a TC1 component tester, and I can say the value shown by this tester was way out of line !
I would encourage you to do the same tests as well.

When measuring a power transistor like a 2N3055 you need lower values for the resistors: I took Rc=270ohms/5W, Rb=27K and emitter directly to GND.
Now adjust the power supply voltage so that the base current ranges say from 0,2mA upwards to 0,7mA or so.
Then note the corresponding collector currents, and calculate Ic/Ib=hFE
You may be surprised of the variation...

And if you have various transistors of the same type, it is also interesting to repeat the above test with a number of them.

I think you will find that hFE values are to be interpreted carefully.
Jeff eelcr:
Fluke service manuals had a circuit you can build for units that measure seimens (conductance).
Its not perfect but does work.
Jeff
Kleinstein:
The DMMs usualy measure Hfe as the large signal quantety and not hfe als the small signal parameter. The gain is not strictly a constant, but it can vary.

With modern circuits the actual gain is usually not a big deal, they are usually made to tolerate quite some variations, even if this means using more transistors. In addition the modern silicon transistors usually have a pretty stable gain. Measuring the gain was mainly an issue with germanium transistors, where the gain was more likely to change (e.g. with time or heat) and parts were scattering more.
Today the Hfe measurement is more like a function test and verification to have the right pin-out.

The DMMs removed the transistor test, because it is very difficult (nearly impossible) to meet the modern safty standards with this. So today the transistor tester is more like a separate instrument or a simple DIY circuit: send a small (e.g. 1 µA)  essentially fixed current to the base and measure the collector current. Power transistors anyway need a test at a higher current than small signal ones.
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