> It's not even isolated from mains. What happens if there was a power
> surge? Dead.

Yes, very dead.

The multiple resistors in series is a nod to safety, but it's still not saf=
e.

Consider if Phase (Hot) and Neutral (Cold) were transposed once (or any odd=
=20
number of times) in the supply wiring then the user would be directly conne=
cted to=20
Phase via no resistors. For a country with a MEN (Multiple Earth System) wh=
ere=20
Earth & Neutral are bonded together the test dummy/patient/person is likely=
 to be=20
(and Murphys Law says they will be) standing on or touching something at Ea=
rth=20
potential. Serious death shocking will occur. Such installation wiring tran=
spositions=20
are not uncommon and can go undetected till something else goes wrong, like=
 this.=20
Series resistors in both arms of the circuit would be an improvement, thoug=
h fault=20
current then would still be 2x design current.

The instruction to use one hand to hold the unit and the other to turn the =
knob also=20
freaks me out. Cross body current we are told is far more likely to pass th=
rough the=20
heart. Another reason to get dead. Instructing the user to operate the devi=
ce with=20
one hand and keep the other hand in their pocket would probably still be sh=
ocking=20
enough for demonstration purposes (finger to palm). But advice alone won't =
render=20
safety, misuse will still kill.



--=20
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