Part 1: http://www.youtube.com/watch?v=sUG_sjS67K4
Part 2: http://www.youtube.com/watch?v=weJ4JdFat8o
Dave dons the lab coat for yet another installment of the Unusual Oscilloscope Phenomenon
Part 2: http://www.youtube.com/watch?v=weJ4JdFat8o
Dave dons the lab coat for yet another installment of the Unusual Oscilloscope Phenomenon
Unproper grounding , you get some from sw pwr. Call fling ground, difference beatwine ground and probe can be even up to 700, but so weak in wires can be mesured in low voltige seting 1v, 0.1v per div.
Its not phenomen…
Old tt instruments use galvanic separation with diode and resistors to make fling ground an potetial about 40- 50v DC curent…
after 11 years Im still having this problem , did you find a resolution ? better shielded cables, farad clamps ?
I think it's just your… vibrating personality 😉
I know this is a old video, but the fact is simple, arround ten years ago, i experienced similar phenomenon.
Every time I got up from my office chair and touched something metal or i shake someone's hand, i felt and hear the electrostatic discharge.
I had this never before, but that day i was wearing new shoes, the day after when i weared my older shoes, i didn't experienced any electrostatic discharge or whatsoever.
After that, everytime when i wear the new shoes, the major electrostatic discharge was back when standing up from my office chair. So in short, the clothes and/or shoes that you wear, plays a big role whether or not you experience electrostatic discharge,
and it's this electrostatic discharge that oscilloscopes pick up.
Repeat the experiment with different shoes, and the results will change.
Does it still happen while running sprinklers in the lab?
Would be interesting to see how far away from the scope you can be before it stops picking up the static.
Dave, did you try this with an isolated power supply (Maybe battery powered oscilloscope) and able to reproduce this phenomenon?
Dave, U are an exceptionally hot guy, I don't know if ur wife agrees. ha
Our bodies work as a capacitor, and a transmitting antennae, rubber sole shoes can amplify the phenomen
I've seen this measuring photodiode currents directly. You have to be careful moving your wheely chair!
:-O !!
Common factor in all experiments is the ESD solder pad on the table.
Now you have me thinking. Those grounding leads are almost all coiled for easy movement and less tangling/interference with other nearby objects. While for ESD elimination for handling parts it's great, it will have a higher impedance to higher frequencies. Like your overall point of spurious measurement, it's just something to be aware of.
Magical chair. Producing static charge. Lol
I came across this same phenomenon about ten years ago when it was causing board resets every time I stood up. I found a paper that showed it was electrostatic discharges within the foam rubber in the chair. This is a known issue.
I commend you for sacrificing your chair for science.
Great series. For the most part you summed it up well. Thanks.
maybe it's not YOU who produce this EMI, but the chair itself? and it doesn't depends of your clothes? what if You will use wooden chair?
Out of a habit I always touch my chair with my foot first, and when humidity is low, my scope triggers at that point.
Wow, is that a floppy drive on the bottom of that scope?
I believe You in 100%!
From the very begining!
Every time you stand up, you block our view of the 'scope, and we can't see it triggering. Also wondering if there's any difference if the 'scope is not sitting on the grounding pad. I saw the test with the anti-static lab coat, but are your shirt or pants made of polyester? What else in the environment might be causing a static discharge? Interesting stuff! Recently found your blog and am working through it.
HhhahahaLOLOLOL! Amazing how many people can't take what it is for what it is at face value. Why don't you just build an aluminum foil faraday-cage around the oscilloscope and anything else you can think of, and try it again? LOL!
I think it is an EM pulse generated by the static electricity which is picked up by the wiring and then causes a resonance effect in the shorted probe/scope input circuitry. The higher frequency generated when just the input socket is shorted (lower inductance/higher resonant frequency) would tend to support this explanation
mechanical vibration in scope
I think that you are all mistaken. That is the key