On 11/30/2018 6:51 AM, Muddymike wrote:
On 29/11/2018 20:30, Bruce Farquhar wrote:
Those cheap Chinese water heaters which are simply two plates of
metal, one on live and one on neutral, how can they work?* Because the
resistivity of tap water apparently varies from 2 to 200 ohm metres.
That's a range of 100 fold in possible power output.* I assume the
resistivity changes due to impurities like lime in hard water areas?

They work best with Chinese water which is full of crap:-)

Mike
When I was a kid, we had a vaporizer that used 2 carbon rods, which were
in a Bakelite tube, with the whole thing submerged in a large water
bowl. It worked, but, even though we had city water (Chicago area), the
carbon rods would get coated with minerals and would have to be cleaned
from time to time. Otherwise, the output would be very low.