aldo_huxley wrote on Aug 24
th, 2003 at 1:48am:
So how many manufactures are they? What components are common? Just curious. Mainly interested in the type of sensors and IC's utilized.
I'm not sure how many manufacturers there are, but Lafayette Instrument Co. is one of the biggest suppliers of polygraph instrumentation:
http://www.lafayetteinstrument.com Quote:Oh yes, a friend of mine is replacing a cap in an old stereo system. Question posed is which type is best, electrolytic, mylar, or ceramic? The former is best for filtering but I'm not sure about it's general effect on the sound. Any ideas?
Was the cap in the audio path to begin with, or in the power supply? In general, I would replace it with something close to what you took out.
For the record, electrolytics aren't necessarily "the best for filtering". Again, it depends: upon the frequency range of noise you're looking to filter, the noise amplitude, and how much you're looking to spend. Usually for power-supply-pin bypassing, you'll find both electrolytic and ceramic in parallel to cover a larger frequency range for noise filtering (most electrolytics are pretty much useless by the time you get into the tens-to-hundreds of kilohertz range).
Quote:Gee, went off the subject.......
So you think the EMI protection within the unit exceeds the ability to disrupt it's functionality?
Absolutely not. But it all depends upon the strength of the disruption practially available, of course.
I would imagine some sort of high-voltage spark-gap device would likely induce significant noise in the GSR channel, at least. Whether the noise-induced nature would be obvious is another question.
It would be an interesting experiment to do, and could be tested using a common multimeter, unshielded leads and spade connectors strapped to the index and ring fingers using velcro straps (yes, I made my own crude GSR meter).
Skeptic