A low DC voltage is produced by the thermocouple when the two junctions are at different temperatures. This voltage is referred to as the thermoelectric voltage. This thermoelectric voltage is produced by the temperature gradient along the thermocouple wires.
Re: What's causes the electric shock type pain in a tooth Hi DM69. I'm not a dentist but I'm pretty sure its the erosion of your tooth exposing the pulp, I had the exact same feeling in my tooth before I had it extracted a month ago, so I feel your pain.
The causes of hypovolaemic shock are : Loss of blood, which may be revealed or occult. Trauma, which may lead to visible bleeding or rupture of an internal organ like the spleen or liver. A fractured femur will bleed about half a litre and a fractured pelvis will lose about one litre of blood - note these volumes vary according to age/weight.