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RE: HFAC safety

Posted by megasat16 on January 7, 2017 at 13:02:35:
The current of 1uA at 1000v is much more dangerous than at 10V. The normal heater voltage for the filament is around 20V or less so it is well below dangerous level even at around 200KHz or 2MHz HFAC is applied at these low voltages. The normal skin resistance varies from places to places on the human body. Skin on the hands and foot are thicker so they have higher resistance. So, a lot of variables in play here.
But it sure is dangerous to touch the low voltage HFAC or DC or regular AC filament wire when the B+ potential is applied to the tube. Normally, it would be OK but in some cases with failing tubes or God knows what else; the leakage current from HV B+ may flow through your body.
A function generator can be set to 20V at 200KHz HFAC (square / sine / triangular, rectangular) and you can hold the lead without any adverse side effects. So, it is mostly quite safe but does not mean absolute in anyway. But cracked skin, wet skin, thin skin, and a thousand other things can reduce the normal skin resistance to considerable level so never say never and better not touch any bare wire or electrical contacts when power is applied. Accidents do happen and many have lost their lives over charging a cell phone.