Thermosensitive resistance element

675,730. Temperature-variable resistors; non- metal resistors; casings, enclosures and mountings for resistors. STANDARD TELEPHONES & CABLES, Ltd. Jan. 30, 1951, No. 2298/51. Class 37. To reduce heat losses in an indirectly heated thermistor assembly the heater winding 7 has leads coiled as at 9, 10 and is arranged to enclose a section of each of the thermistor fine-wire terminal leads 2, 3. The latter, as shown, emerge from one end of the heater winding 7 and from within a cylindrical casing 6 of electrically non-conducting cement at whose centre is embedded the thermistor bead 1. A metal tube 8 with a polished outer surface surrounds the heater winding 7 and has dimensions to ensure that by its presence there is improved heat resistivity. The assembly supported by-heater winding lead-out conductors 11, 12 is mounted in an evacuated envelope. Specification 555,563 is referred to.