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.
Occipital neuralgia can cause intense pain that feels like a sharp, jabbing, electric shock in the back of the head and neck. Other symptoms include: 1  Aching, burning, and throbbing pain that typically starts at the base of the head and goes to the scalp.  Pain on one or both sides of the head.