EEVblog #14 - An unusual oscilloscope phenomenon!

[jewishcrimenetwork]

It might also be that the way you shortcircuit the probe is creating a solenoid (a 1-turn one) loop.

Could you try it again shortcircuiting without the loop?

[Films4You]

You don't get this with those cheap USB oscilloscope, LOL

[pugleo]

I think It's your chair. I used to field service and had a problem with a user's terminal shutting off. It turned out that the nylon bushing in the chair acted as a static generator. When the person got up off the chair, and the chair rotated, the back of the chair would touch the keyboard of the terminal. The resulting static discharge would shut the terminal off. Note your event happened when you got up from the chair.

[EEVblog]

@pugleo Of course it's the static caused by the chair.

[ThinkLearnSolve]

@EEVblog nice investigation, curious if you can tried generating static manually on a larger scale

[dynetrax]

@pugleo lol did you watch the entire video before commenting? I'm just wondering.

[Desmaad]

I've read that air core inductors--like your probe cable--can pick up vibrations, known as "microphoning". Have you considered this might be the problem?

[EEVblog]

@Desmaad It's definitely proven to be static, nothing to do with microphonics.

[thomasey2]

That was a good video

[razean22]

the shape is a sinus cardinalis, the fourier transform of a rectangular signal and since FT works in both ways, there has to be some interesting mathematical background. im trying to figure that out :)

[kktech04]

Excelent video. I'm watching each one of the videos of your blog, and all of them are just great. BTW, my wife took a glimpse to one the them and said "his room looks like yours". Great stuff !

[Flixan]

Before I even started the video I was guessing the the probe was acting as a magnetic B-dot probe, picking up the emi from the static electricity. In my lab, we short probes like this and hang them over the near a Marx generator and look at the trigger waveform for quick on the spot frequency diagnostics.

I love these videos though.

[Flixan]

@Flixan hang them near* triggered single shot waveform*

[stivep1]

(20 years in science...applied one...) YOU ARE  AMAZING KEEP ON GOING YOU HAVE REAL TEACHING SKILLS .

You make the world better,and future of many young potentials.

Thank You For Your Work

[miro9406020601]

good jov exelent videos ! ceep on going

[hityou123]

I had a similar experience. The waveform on the scope would move when I waved my hands over the circuit. I found out it was bcoz of the sweater I was wearing. I took it off and what a relief.

I am pretty sure, if you are careful with what you wear, you will see less of the glitch.

[woodlanduk]

Hmmm me thinks you need to build a Faraday cage and ground all static generating systems including you :0) great experiment though.

[Afrotechmods]

I discovered the same thing a few years ago! I added a sheet of aluminium foil as an 'antenna' and a peak detector circuit and created a very sensitive motion detector. It was able to display my footsteps as I was walking around the room or waving my arms. It was probably more effective than most infrared motion detection systems! It only worked in 0% humidity though.

[kchididdy]

Is it the corona discharge that creates the broadband EMI? Very strange.  Is it worse on dry days? I has nothing to do with your chair, right? maybe some kind of pseudo-piezoelectric effect from the chair piston thingy?

[japroach]

Yes ESD would be worse on a dry day, and could definitely be affected by the fabric type on the chair (not due to the piston though).

[waynevict]

Could this set up also pick up the neuromuscular impulses?

[EEVblog]

I filmed a comment that I have seen it happen from several meters away, but it didn't make the final edit due to time constraints.

[JINXZER]

Thats good to know I wonder how far it can pick up from? do you have to be close to it? and do they use that sort of stuff in sensors? bahh i dont know what im talking about of course not oscilascopes are sensitive equipment.