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.
A fracture of the jaw, oral surgery that injures the nerve to the tongue, and nerve pressure from a tumor can all cause nerve damage that may result in a tingling feeling. Heavy metal intoxication and radiation exposure are other possible causes of this issue, states Healthgrades.