ID: 
2046
Maker's Name: 
Unknown
Where made: 
England
Dimensions: 
0.9 × 0.9 × 9 cm

A couple consisting of two dissimilar conductors is heated by a coil of resistance wire. The wire and coupled are isolated electrically, but coupled thermally. The heated couple produces a voltage, dependant on the conductors used and the temperature of the couple. This is called the Seebeck Effect. This thermocouple was probably used to measure an alternating current flowing in a circuit. The B14 marking on the envelope suggests that the couple is a PN semiconductor junction. This has a higher voltage output than a metal junction.