Since I was around 6 or 7 I liked to touch an ****** just for the sensation feeling, and later for the "waked up" feeling. It's probably a good discussion topic for Physicists or EEs, but it could probably be a prohibited topic.
You must be kidding! I'm the opposite. I'm zipped almost everytime I plug my metal thumb drive into a PC at work. Even when touching my laptop when opening the lid. And I have to disconnect the VGA cable before touching my CPU casing. Shoes, newspaper or even plastic under my foot didn't prevent this from happening.
This is I don't understand. I assume that VGA cable has low voltage and when I touch the VGA pins nothing happened, so why when it is connected to a CPU the CPU casing becomes "alive" (must be the switching supply)?
Last edited:
Jay,
I am one of those who have very dry skin, so dry that I have problems with touch screens and anything that relies on inductive pickup. I've shown my kids many times that though they can swipe something and have no problems I can do the same over and over and get no response. How the moisture level in the skin changes all that I am not sure as I assure you I do have good blood supply to my extremities. You may just be the opposite and have very high moisture levels at the skin surface. Perhaps it is actually you that is carrying the surface charge and the equipment you are touching is grounding out your surface charge or it is the clothes you wear. I don't know but others may have those types of answers. The environmental conditions also have a lot to do with surface charge.
I am one of those who have very dry skin, so dry that I have problems with touch screens and anything that relies on inductive pickup. I've shown my kids many times that though they can swipe something and have no problems I can do the same over and over and get no response. How the moisture level in the skin changes all that I am not sure as I assure you I do have good blood supply to my extremities. You may just be the opposite and have very high moisture levels at the skin surface. Perhaps it is actually you that is carrying the surface charge and the equipment you are touching is grounding out your surface charge or it is the clothes you wear. I don't know but others may have those types of answers. The environmental conditions also have a lot to do with surface charge.
So it is about moisture? Still a mystery to me how the sensation work. But I know about "funny" bone, just below your elbow. If you "hit" the spot with your finger nail you will feel the same sensation as being zipped by 220V. It is said that this spot has the closest distance to a "neuron" or sensor in the brain.
Interesting. There is a stone that is popular around this year, due to it being used by the president (in a ring) and also the same stone being given to Barack Obama. Here it is called "bacan" stone. What I don't understand is that this stone can be used to move object in touch screen.
It is probably the high electrostatic charge in my body. Cannot be the clothes because I have many clothes
I hate that everytime I changed the optic in my CD players, no matter what precaution I have taken (I don't have that electrostatic ring/belt), the optic always died.Yes, the moisture level is relatively high here, but the phenomenon doesn't happen with everyone else.
Scott
I am aware of what you say. In the past I had tried again on this topic (and even that approach is simplistic).
http://www.diyaudio.com/forums/analogue-source/100408-results-m97xe-mod-9.html#post1211741
But one has to start from somewhere. The proposed simple test will give a few numbers. Let's look into them ( in ~ a month I will be able to do the test)
When the resistance of the electrical load becomes smaller and smaller, I would expect that the voltage output of the generator with a finite internal impedance (~1kOhm for a MM) will start to drop. Demian has hinted on the magnetics too
George
Only at LF. As the frequency rises, the impedance does as well, exacerbating the effect of the load resistance on output.
If I understand you well, you mean that as freq increases, the inductive impedance of the coils increases, thus the cartridge's internal impedance goes up, which has the effect of further increasing the voltage drop in the process of deliberate lowering the resistance of the cartridge load ( frequency dependence of the series leg of the voltage divider),yes?
George
Applaud the effort, George - however the mechanical impedance does not arise from inertia or mass equivalent of the stylus. I hope I can explain..........
Let's put aside effective tip mass for a moment.
In the bigger picture, if it were not for mechanical impedance to motion of the stylus, there would be no need for downforce to keep it tracking groove motion. Then, it is possible to determine mechanical impedance versus frequency from measuring the limit of trackability velocity versus frequency, and this is what was done by manufacturers back in the day. There were published mechanical impedance curves for some cartridges, I've attached an example for a Denon DL103.
By reading the mechanical impedance curve, one can readily obtain mechanical power required to move the stylus at any given velocity and frequency. This is the best way to evaluate mechanical power involved in stylus movement. When we do this, we find it works out perhaps a few mW typ at 5 cm/s 1kHz.
Returning to effective tip mass, in principle it is what determines mechanical impedance at high acceleration, ie high frequency, the right hand part of the impedance curve. HOWEVER, the method typically used by manufacturers to determine effective tip mass is seriously flawed and does not correlate well - it assumes vinyl is springy and then determine e-mass from the mechanical resonant frequency always observed in the cartridge frequency response. Whereas this resonance can be that of cantilever self flex, not related to vinyl spring-tip e-mass system at all. Poor correlation obtains from using published tip mass as a figure of merit then, other than to locate the frequency of the mechanical resonance - it is useless for evaluating mechanical impedance and power for example.
Best to use the published mechanical impedance curves then, eg in the example below. So, for MM, typical power conversion ratio when loaded at 47k works out about -45dB or about 0.002% (NB that is a power ratio).
Edit: also added a published Shure V15 cartridge mech impedance chart
Attachments
Last edited:
- Status
- Not open for further replies.