Weird DMM Readings

Thread Starter

ben sorenson

Joined Feb 28, 2022
180
Hello, I have a question about what may be causing some weird readings on my DMM. It's not a fancy unit, I purchased it from NAPA for around $100.00 it does however have a multitude of functions AC/DC current, Pulse Width, Frequency, Diode/Cap check etc... The issue that I'm having is when I run this electromagnetic contraption that's been made, if the multimeter is near the device (while running) and set to the ohms position (multimeter leads not touching anything) instead of sitting there at OL it will start reading high resistances. If the multimeter is set to the AC or DC volts position when the device operates the multimeter acts like it is being used beyond its normal voltage rating, every word, symbol and indicator light on the DMM will illuminate..this happens with other multimeters I have as well.

Is it possible in the presence of a strong electromagnetic field, if the device that is causing all of this is putting out frequencies in the RF range, could the internal zener diodes in the DMM be "triggering" sort of acting like PIN Diode Geiger? Detecting RF frequency? Only thing I can think of that would be causing something to happen like that.
 

sagor

Joined Mar 10, 2019
909
What happens if you remove the leads? What happens if you short the leads?
Both those tests may tell you something. I suspect the unterminated leads are acting like antennas, bringing any electrical noise into the DMM.
 

WBahn

Joined Mar 31, 2012
30,045
Why do you think that the only mechanism that can explain it is internal zener diodes triggering and acting like a PIN Diode Geiger?

Why can't the electromagnetic fields being generated simply be inducing voltages and currents in various parts of the circuitry causing it to thereby misbehave?
 

strantor

Joined Oct 3, 2010
6,794
I'm not saying you're recreating tesla's wireless power devices in your basement, but if you're recreating tesla's wireless power devices in your basement, don't post about it here. "They" monitor this forum.
 

Thread Starter

ben sorenson

Joined Feb 28, 2022
180
What happens if you remove the leads? What happens if you short the leads?
Both those tests may tell you something. I suspect the unterminated leads are acting like antennas, bringing any electrical noise into the DMM.
Actually, now that you mention it, getting annoyed at the chances of destroying another multimeter I have disconnected the leads on a few occasions and it did not read any voltage. However I ran the device last night and came across a simular issue. I have a GQ Geiger Counter mounted about 3 inches from the "source" it was not picking up any CPM's but after a min or so of run time the OLED screen was doing the same thing as the multimeter where all available indicators were "blurred" or "strectched" accross it. I had to remove the battery in order for it to work properly again. This is the second Geiger counter I have gone through so I don't want to break it again, the 1st counter I used just randomly stopped working, as every time I would run the "source" I would get incredibly high readings, when it finally stopped working I had disassembled the counter to find out the 3.7 lithium ion battery was bad. (The Geiger was brand new and not mishanded,, dropped, etc) I tried a new battery on that unit and it did not fix the issue, I ultimately found out there was a issue with the battery supply circuitry as I was able to power it via USB. But I didn't trust using it anymore. Not sure how a battery or its circutry could go bad without any physical connections... idk it's just weird. Another issue I ran into was that whenever I ran the "source" my Wife would complain that the TV in the room would have a problem with the audio, it was cutting in and out. I did listen to the issue and sure enough when the "source" was on the TV glitches and sounds like a scratched or skipping CD.
 

MrChips

Joined Oct 2, 2009
30,795
If your "source" is being powered by high frequency high voltages, you are very likely emitting a lot of RF interference.
Any type of electronics in the vicinity will be subjected to a lot of EMI abuse. Anything can result from that.
 
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