Author Topic: Fluke 179 Diode Test  (Read 396 times)

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Online Electro Fan

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Fluke 179 Diode Test
« on: Yesterday at 01:53:31 am »
Anyone happen to have a Fluke 179 that shows about 7.3 volts on the diode test?
 

Offline paulbt

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Re: Fluke 179 Diode Test
« Reply #1 on: Yesterday at 07:50:58 am »
Anyone happen to have a Fluke 179 that shows about 7.3 volts on the diode test?

Hi, please post a picture with your setup.
"Simplicity is the ultimate sophistication."  Leonardo Da Vinci
 

Offline coromonadalix

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Re: Fluke 179 Diode Test
« Reply #2 on: Yesterday at 02:28:59 pm »
yep  same thing  ....  post your setup

this meter should go up to 2.4v     specified in the data sheets ...
 

Online markce

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Re: Fluke 179 Diode Test
« Reply #3 on: Yesterday at 07:39:08 pm »
My Fluke 175 also has 7.3V output in diode test.

What is specified is the max diode voltage that can be measured, not the test voltage.
So I can test a 2.1V stabistor (integrated 3x Si diode), but not a 2.8V stabistor.
« Last Edit: Yesterday at 09:39:18 pm by markce »
 
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Offline tubularnut

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Re: Fluke 179 Diode Test
« Reply #4 on: Yesterday at 07:46:54 pm »
Like this?
« Last Edit: Yesterday at 07:53:23 pm by tubularnut »
 

Online Electro Fan

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Re: Fluke 179 Diode Test
« Reply #5 on: Yesterday at 08:59:23 pm »
Like this?

Sorry it took me a while to get back to this thread but yes, just like that.
 
 

Offline tubularnut

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Re: Fluke 179 Diode Test
« Reply #6 on: Yesterday at 09:24:05 pm »
Yes, very odd, not something I've not tried before, and the spec does say 2.4 volts as mentioned by coromonadalix

The Brymen shows 2.9V. The spec sheet says 2V but also an open circuit voltage of <3.5V, so maybe it has something to do with being (effectively) open circuit?

I'm sure someone will come along and say we are doing it wrong  :-//

PS. Apologies for the grubby look of the 179, it's my 'outside' meter, and well used.
« Last Edit: Yesterday at 09:26:16 pm by tubularnut »
 

Offline PushUp

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Re: Fluke 179 Diode Test
« Reply #7 on: Today at 12:55:07 am »
The only device I have, is the "atlas Peak ZEN50", which is able to measure such high values in forward voltage mode.



The first LED shows 2,63V and you see at least a flickering while testing - probably not on the picture, the second LED shows 8,50V and is not lighting up @ 2mA any more.


From my experience, the better Keysights have the highest capability, but not as good as the green lantern from above.  ;) In this case my good old Hameg with its componenten tester, is the only device to illuminate the LED with probably 5-6 V(f) - no other from my DMMs can do so.




Finally an example with an voltage regulator. Only Keysight and my HMC8012 are able to show a value - both 179 and 289 only "OL".




Therefore the value of 7,298 VDC in diode mode against another DMM does not stand for the real capability of the DMM in normal bench usage - unfortunately...  :(




Cheers!  :)
Due to the massive "EEVblog forum attachement bug", I am now using an external picture hoster, till it is solved...
 

Online Electro Fan

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Re: Fluke 179 Diode Test
« Reply #8 on: Today at 05:14:42 pm »
Thanks for the various test results and posts but I'm still trying to sort out the various meter specs as they relate to the results.

Apparently some meter voltage specs for diode testing are an open circuit value and some specs better reflect voltage under some (generally not specified) load?

Maybe what we are seeing is that DMM voltage specs might or might not specify everything needed to fully understand the diode test capability?  Maybe the diode specs don't always show or reflect the DMM test's current limit value for the diode test?
 


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