[sdiy] Diode Matching

Ingo Debus igg.debus at gmail.com
Fri May 8 20:57:00 CEST 2020


> Am 11.04.2020 um 01:12 schrieb Didier Leplae via Synth-diy <synth-diy at synth-diy.org>:
> 
> Incidentally, if I change the multimeter to read another diode, the reading stays at the elevated reading, 365mV. So that suggests to me that the meter is what's heating up, or causing the change, rather than the diode.

While we’re on the subject, there’s a funny thing I observed on my DMM measuring resistors. When I connect a 560 kOhms resistor the DMM shows something like 0.565 MOhms. It drifts a little, but not much. Now, when I grab one of the test lead, just the isolation, without making contact to the wire, the value changes drastically. When I grab the other lead, the values changes into the other direction. Seems like a mains hum probrem to me.
On the other hand, with a 470 kOhms resistor the displayed value is rock stable. 

Funny, eh? That’s an old battery operated Voltcraft multimeter, not a very expensive one.

Ingo



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