Re: Estim Dual Channel Videos
Posted: Sat Nov 19, 2022 2:04 am
The DC conversion method is just giving you the A-B difference in a single channel so you don't need a third conductor. In other words, it's the same as connecting for tri-phase but only attaching A and B to your body and not attaching the common to your body. The other polarity DC conversion is A+B which is like making the common out of the red of one channel and the black of the other, then likewise not putting the common on your body.
The reason dual channel feels more gentle is that the "A-B" and "A+B" are not referenced to each other, so they actually float with respect to each other as the signal changes. It's like if you are straddling two skateboards and it's very bumpy as they push your feet in different ways, then you put shock absorbers on one or both, and that takes up some of the pressure. The shock absorbers are the resistances in your body between each combination of electrodes. If you attach the common to yourself along with also that A-B and A+B, that is like taking away the shock absorbers, because now those voltages are rigidly referenced to the same frame, and every little wiggle forces current into your body.
In plain tri-phase, you feel A+B at the common and mostly A-B between the A & B (there's actually another effect that depends on relative resistances between A & B versus A to common and B to common, but ignoring that for this). So dual channel is giving you a similar feeling but without that extra effect and also with the gentleness from not having that common attached.
BTW, LondonGent, thanks for your clever method of converting tri-phase to dual channel!
The reason dual channel feels more gentle is that the "A-B" and "A+B" are not referenced to each other, so they actually float with respect to each other as the signal changes. It's like if you are straddling two skateboards and it's very bumpy as they push your feet in different ways, then you put shock absorbers on one or both, and that takes up some of the pressure. The shock absorbers are the resistances in your body between each combination of electrodes. If you attach the common to yourself along with also that A-B and A+B, that is like taking away the shock absorbers, because now those voltages are rigidly referenced to the same frame, and every little wiggle forces current into your body.
In plain tri-phase, you feel A+B at the common and mostly A-B between the A & B (there's actually another effect that depends on relative resistances between A & B versus A to common and B to common, but ignoring that for this). So dual channel is giving you a similar feeling but without that extra effect and also with the gentleness from not having that common attached.
BTW, LondonGent, thanks for your clever method of converting tri-phase to dual channel!