Buying a new multimeter: how important is hFE?

Thread Starter

waverider

Joined Jul 1, 2020
3
Hey,

I'm buying my second, better, multimeter (first one costed 3 € : ) ) and I have this checklist:

* auto ranging
* capacitance measurement at least up to 10mF (I see a lot under 1mF and that sounds pretty useless)
* ? hFE - how important is this one? It sounds pretty useful to me
* I've noticed other interesting features and I'd pick them (more is better, right?): frequency, filling factor (?), dB (though this is rare in multimeters)

Other notes:
* It should be decently accurate and reliable, but not a professional, expensive tool
* I'm a hobbyist doing electronics, home automation, possible audio stuff in the future. I won't mess much with mains, if at all.
* Budget: up to 50€ (may go up to 100€ if justified).

My problem is that it seems pretty hard to find all this in one piece: auto ranging + 10mF+ capacitance range + hFE.

For instance UNI-T UT61E has decent reviews, is affordable, ticks all requirements, except hFE.

So how important is hFE feature?

What other important features would you suggest?

Can you suggest a particular model with these features?


Thanks
 

WBahn

Joined Mar 31, 2012
25,914
Whether or not having a meter than can measure hFE is important depends entirely on how important it is for what YOU do to be able to measure hFE.

So, how important is it to YOU to be able to measure hFE?
 

Thread Starter

waverider

Joined Jul 1, 2020
3
I guess hFE measurement is good to have. I've only started with electronics a couple of months ago, so things are a bit fuzzy for me.

I'm curious if have and use hFE on your meter.
 

ZCochran98

Joined Jul 24, 2018
83
Do you want to measure the current gain of a BJT transistor without setting up a circuit to do so or relying on the datasheet alone? If you do, then the hFE feature is very useful. I've had hFE on every (good) meter I've bought, and have used it a few times to verify a BJT's current gain.
 

ZCochran98

Joined Jul 24, 2018
83
Do you want to measure the current gain of a BJT transistor without setting up a circuit to do so or relying on the datasheet alone? If you do, then the hFE feature is very useful. I've had hFE on every (good) meter I've bought, and have used it a few times to verify a BJT's current gain.
As a small side note, I just realized that I wrote a redundant statement: "BJT transistor" is the same as "bipolar junction transistor transistor." It's like writing "PIN number" or "ATM machine"
 

dl324

Joined Mar 30, 2015
10,953
I'm curious if have and use hFE on your meter.
I have several DVMs that have it. I've used it a few time, but a curve tracer is much more useful; assuming you have a scope.

Personally, I don't have much use for autoranging meters; they take too long to settle.
 

rsjsouza

Joined Apr 21, 2014
248
The hfe measurement on a multimeter is useful for a quick check of a transistor's functionality. This check can also be done using the diode function and traversing all pins of the transistor, but the hfe is a single shot check.

However, its advantages don't go very far from there. The reason is that it only measures the DC gain at a given bias point, typically at a very low voltage and current. A transistor is a much more complex device that has a range of bias points and voltage ranges where its parameters such as hfe can vary. Also, a power transistor's parameters are quite different than a small signal one.

In summary: I don't think the hfe is a "make or break" feature of a multimeter. Also, keep in mind the correlation between lack of safety and the presence of a hfe feature is pretty high for the options available in the marketplace. If you don't intend to use it in any high voltage electrical system, you should probably be fine.

One last aspect: the UT61E has hfe feature by means of an external adaptor. I personally like this meter for low power electronics, but some reports indicate it can lose its calibration over the years due to the quality of its internal trimmers. I have one for about 3 years and haven't had problems yet.
 

SamR

Joined Mar 19, 2019
2,259
In my way of thinking there are DMMs (V, A, Ω) and then there are component testers (Hfe, H, F). And each has a very nice place on my bench. I typically use the component tester more for quickly determining the type of xstr and which leg is which more than for Hfe. Anything more than that is on the PDF, read it! It is also nice to measure H & F when picking a component to use as a double-check against its markings, not very often, but useful enough for me to buy the tester and keep it charged. Then some DMMs have a few extra frills, temp, freq, continuity/diode, capacitance, and some even inductance. What do you want to use and when? It's all up to you. My goto meter is a Fluke 27 which is a DMM that only does V, A, Ω, and continuity/diode. It does have some rarely used buttons for MIN/MAX and Rel for zero setting. I went for rugged, dependable, accurate, and simple. I have other meters and testers for the bells and whistles. For a hobby user, a simple ~$20-30 meter fits the bill nicely as a start.
 

MrChips

Joined Oct 2, 2009
21,329
To echo what others have already experienced

1) My meter has hFE and I have yet to use it,
2) I dislike auto ranging
3) A meter is not much useful for audio stuff. What you need is an oscilloscope.
4) Designing a meter to measure capacitance below 1mF is not difficult. If you want to measure >1mF you need special instruments.
5) Yes, you will use your meter for mains AC, much better than using your finger or tongue.
 

sparky 1

Joined Nov 3, 2018
260
The datasheet tells you the hFE. Bells and whistles have no end. The parts inside count when you adjust something precise like a voltage reference needs to be between 4.9164 - 4.9170 Volts. So depending on what you are doing. Save money and don't get started on really precise stuff so 4-1/2 digit projects wait for bench meter.
 

WBahn

Joined Mar 31, 2012
25,914
I guess hFE measurement is good to have. I've only started with electronics a couple of months ago, so things are a bit fuzzy for me.

I'm curious if have and use hFE on your meter.
Why do you guess that it is good to have?

I have a couple of meters with hFE capability. I've never used it "for real" -- I probably used it out of curiosity on the first meter I had that had it, but I'm not even sure of that.

Designing circuits that depend on a transistor having a specific value of hFE is very bad practice. Generally you design your circuit so that as long as its gain is within some range (usually just as long as it's more than some minimum) your circuit will function adequately. Then you select a transistor whose data sheet shows that it meets your specs.

But even if you are designing for a specific value of hFE for some reason, hFE is not a constant -- it depends pretty strongly on operating conditions and so the only value of hFE a meter will tell you is what the hFE is at a specific operating point which is pretty much guaranteed to NOT be the operating point your circuit will be operating at.

About the only thing that the hFE test would be useful for is telling you whether a particular transistor might be bad (notice the use of the word "might").
 

SamR

Joined Mar 19, 2019
2,259
The Hfe number my tester gives me is "amusing" and basically useless. What the Hfe actually is in the circuit will not match what it gives. That it gives one might be a clue as to whether the xstr works or not and there are other ways to test. IE, NO you don't need Hfe on a meter. You need what you will use.
 

Thread Starter

waverider

Joined Jul 1, 2020
3
I'd use hFE rather to test if transistor is broken, not necessarily for an accurate value. Otherwise, yes the technical sheet would be enough. Regarding the testing transistor with diode test: should I also have the based polarized from a small power source. Or how exactly is this done just with the meter, without a simple circuit?

@dl324 @MrChips I'm curious what do you see wrong with auto-range? They seem to me pretty fast to settle, anyhow faster than me moving probes between 2-3 ranges ... And some meters (like UT61E I think) also allow manual ranging.

One last aspect: the UT61E has hfe feature by means of an external adaptor.
I've noticed the adaptor with the transistor socket, but I thought it's same adaptor for other meters that actually have hFE (based on this review: youtu.be/Bz6CYDRl1M8 ). Do you have a reference for this info?


Why do you think measuring <1mF is useless?
Indeed, not completely useless, but I'd expect to be able to measure for instance 3200μF capacitors. Some meters have <200μF or <100μF range.

Thanks everyone
 

schmitt trigger

Joined Jul 12, 2010
277
Same here, never used the Hfe capabilities of the meter.
If I were you, I would remove that functionality from a DMM wishlist.

What I do have is a separate instrument: a semiconductor analyzer from Peak Atlas.
Have had it for over 10 years now, and I am extremely satisfied with it. (I am not getting any royalties from PA!)
There are cheaper brands on Ebay.

This basic Semiconductor analyzer will provide simple stuff like Vf, Hfe, Vbe or Vth, but its real usefulness is in *automatically* identifying the component type and labeling the terminals.
That on itself, has saved me countless frustration, specially with SMT devices.

For the DMM one should really focus on accuracy, reliability *and safety*.
Certain additional functions like frequency are OK for quick checkups, where bringing an oscilloscope is not feasible. Audible/visible continuity is also very helpful.
 

KeithWalker

Joined Jul 10, 2017
1,043
I have been dabbling in electronics for 70 years and I made a good living at it too. I have never used hfe on any of my meters.
Don't let the lack of capacitance ranges influence your choice of multimeter. Go for the best you can afford for Volts, Amps and Ohms.
Its really simple to make your own capacitance meter using an arduino and a very inexpensive display. I built one for less than $10.00 CDN and it is quite accurate, certainly enough for my hobby needs. Here is the url and a picture of the one I made:
https://www.circuitbasics.com/how-to-make-an-arduino-capacitance-meter/
C_Meter.jpg
 
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