The voltage pulse from contact port is very brief. Certainly too fast for humans to detect.
The TENS pads connected to the SC is a fixed 100 Hz ultrashort voltage spike of 320v, which is very high, but the duration of the pulse is extremely short. The pulse lasts for less than half a microsecond. A microsecond is one millionth of a second. You will not feel it no matter what you try, and this is a good thing being 320v of power. The pulse waveform is shown below.
It is to induce electroporation of the cells walls (read as reverse the polarity of the cell walls to make them more permeable) assists the plasma.
You probably won't feel the 100 Hz fixed frequency of the PEMF coil either, being that it is an electromagnetic pulse. However, if you are sensitive enough, you may feel a slight pressure in the area it is focused on.
Please check the relevant QA:
If the pulse is too short to feel, why do I sometimes feel a slight tingling?