Ever used the hFE tester on your multimeter?

[eccerr0r]

I found it really irritating and uncomforting to use the hFE checker on my multimeters that have it, so I usually just do diode checks.

Curiosity is, have you used the hFE checker on your multimeter?

[lti]

Re: Ever used the hFE tester on your multimeter?

I tried it on a cheap meter from Harbor Freight, and it was unusable. A transistor that has been removed from a board won't have long enough leads to make contact in the transistor socket on that particular meter. I can measure hFE of a new transistor, but that isn't very useful for me.

[modemhead]

Re: Ever used the hFE tester on your multimeter?

Never. For me, diode-test function suffices for general-purpose transistor checking.

The sockets are unreliable on every meter I've ever touched with this "feature". They all tend to flash a lot of non-sense numbers while you're wiggling it around. I have no patience for that.

If I am really interested in the beta, I'd use a transistor tester where the collector current is known and preferrably can be varied to match the type of transistor.

[momaka]

Re: Ever used the hFE tester on your multimeter?

I've used it a few times when I was building a mini amplifier from discrete parts. Other than that, I don't use much.

I tried it on a cheap meter from Harbor Freight, and it was unusable.

Yes, those cheap HF meters have completely useless hFE sockets, even if you do take a brand new transistor with long leads and try to stick it in there. The socket is so unreliable and flimsy, that I probably would have better luck measuring the transisotr's hFE with my ass. Seriously!

Perhaps I should mention that I use the hFE tester only on my Radio Shack meter, which is not exactly a cheapy. Has a very nice socket that is not round.

[eccerr0r]

Re: Ever used the hFE tester on your multimeter?

I'm shocked the HF meters even have hFE at all. I would imagine the typical HF user would not even know what it is...

I also have a Tenma meter with hFE check. This one has a linear arrangement but still suffers from the "lead too short" syndrome trying to test used transistors. Of course when comparing the HF and the Tenma units, the numbers are way off, but at least they're linear to each other (transistors with low hFE will be low hFE on both meters).

I found the round sockets helpful for TO18 and TO5 transistors (and staggered TO92) at least...

[cheapie]

Re: Ever used the hFE tester on your multimeter?

My meter doesn't have that function (and I don't know what it does anyway).

[stj]

Re: Ever used the hFE tester on your multimeter?

i dont think it's much use unless your doing amplifiers and trying to get a "matching npn/pnp pair"
even then, i suspect parts these days have a far tighter spec than they used to back when people matched transistors or valves for audio.

[diif]

Re: Ever used the hFE tester on your multimeter?

So that's what it's supposed to be used for, i wondered when i got my meter.
I have a Peak DCA55 because i'm lazy and i like toys.

[Th3_uN1Qu3]

Re: Ever used the hFE tester on your multimeter?

Used it a few times, and i can recall one time when it really did help. I was still a novice back then, but it came in real handy in finding a bad transistor in an audio amplifier. It showed a hFE of 1, without being shorted or open.

However, most of the times when i DO need to use it, i find it needs the leads of the transistor to be very long to actually touch the contacts inside (in addition to obviously needing to remove the transistor from the board), so i just give up and test it on the diode scale.

[SteveNielsen]

Re: Ever used the hFE tester on your multimeter?

I only used it once to see if it worked.

[redwire]

Re: Ever used the hFE tester on your multimeter?

The only time I measure beta is when building audio power amps that need matched-pair transistors, like the Leach Low-TIM amp using a test jig with 30VDC and a couple milliammeters and a resistor. Then you have to sort and bin the transistors.

Next, I tried my cheap-o $10 multimeter hFE and it's pretty close but only about 5V across the tranny and the reading drifts as the battery sags. Meh.

[nebundemult]

Re: Ever used the hFE tester on your multimeter?

I use this option to distinguish more collector emitter when I doubt about some transistors.

[CapLeaker]

Re: Ever used the hFE tester on your multimeter?

I use it rarely... only to match audio or rf amplifiers.

[Jidis]

Re: Ever used the hFE tester on your multimeter?

Yes, those cheap HF meters have completely useless hFE sockets, even if you do take a brand new transistor with long leads and try to stick it in there. The socket is so unreliable and flimsy, that I probably would have better luck measuring the transisotr's hFE with my ass. Seriously!

I found that same thing after reading people's comments about using it. I couldn't figure out how they got it to work, as I returned my first one thinking it was broken and had the same results on the replacement. Not having a meter with HFE, I wanted to see it work, so I ordered a machined pin socket where the contact holes sit flush with the surface, but I had to extend all eight legs to get it tall enough.

Long story short, I tried a few things on-hand and it surprisingly gave readings almost dead center of the range listed in the corresponding datasheets. I think I also compared against some manual calculations I found using Ohm's law. Not sure how useful it will be, but there was a slight feeling of accomplishment in forcing the feature to work.

Take Care

[momaka]

Re: Ever used the hFE tester on your multimeter?

Long story short, I tried a few things on-hand and it surprisingly gave readings almost dead center of the range listed in the corresponding datasheets. I think I also compared against some manual calculations I found using Ohm's law. Not sure how useful it will be, but there was a slight feeling of accomplishment in forcing the feature to work.

Nice work!

That is actually a great idea there . I do have some SIP machined sockets left over from an electronics class. I'm thinking I could cut a slot on the side of the meter and attach the socket there. It wouldn't look as neat as yours, but it should still work.

Not that I use the hFE feature much, but like you, I would feel a sense of accomplishment if I got it working right.

[Jidis]

Re: Ever used the hFE tester on your multimeter?

If you see a machined pin socket that's tall like the original, I'd be interested, though I'm not sure it's worth modding a second one. The only tall ones I saw look like the stock one, but I couldn't tell if they're any more reliable.

I see some non-DT830's with dual row rectangular sockets. I think that or the single like you're doing is what they probably should have used.

George

[Jidis]

Re: Ever used the hFE tester on your multimeter?

If anybody ever wonders what they're up against with those god forsaken blue sockets, I just realized the old one was sitting in front of me.

rough checks with a caliper:

The blue body is about 10mm deep (diameter is roughly 9), and the pins stick out from the bottom by about 3mm (they're around 6.5 total length). The pins are also pretty "flat". They look to be about 0.3mm thick. So you've got to go about 6+ mm down into the socket before you have any chance of touching that fork thing, and then your leads will need to be thick enough to make contact.

George

[momaka]

Re: Ever used the hFE tester on your multimeter?

^ Good info, thanks.
This gave me a new idea - what if you cut the top part of the socket all the way up to where the pins begin to protrude? I think that might be another way to mod these without buying anything. But how well it would work... I don't know. Might try this instead of my previous idea, though.

[redwire]

Re: Ever used the hFE tester on your multimeter?

Keystone makes transistor sockets.
I bought a tiny breadboard on eBay $2-$4 and use that as a socket for testing large batches.

[Jidis]

Re: Ever used the hFE tester on your multimeter?

what if you cut the top part of the socket all the way up to where the pins begin to protrude?

Yeah, I actually considered that too, but you'd still be dropping the socket way down below the face of the meter. Seems like it would still work, just wouldn't look that good. I was actually thinking of burning that blue one down to size with a belt sander without even removing it. Just make sure you vacuum the holes out or something afterward. I don't think those fork/contact things need any extra help making a flaky connection.

Redwire's link looks like the one I installed. Mine appears to have been this thing by "Mill-Max". Still sits way too low though without extensions.

Take Care