Improvements in or relating to temperature dependent resistances

647,331. Temperature variable resistances; non-metal resistances ; enclosures for resistances. STANDARD TELEPHONES & CABLES, Ltd. Nov. 9, 1948, No. 29085. Drawings to Specification. [Class 37] Thermistor elements or beads are immersed in a suitable insulating and cooling liquid to increase the rate of response to changes in heating current. The liquids .mentioned as suitable are trichloethylene and ethylene glycol and the invention is restricted to these liquids. The Specification includes test data demonstrating the improved time constants obtained for both direct and indirectly heated thermistors. It is stated that the power sensitivity is reduced in the same proportion as the time constant. The arrangement preferred is the usual glass envelope containing the bead and filled with the chosen liquid in accordance with the invention. The beads may be composed of metal oxide mixtures (e.g. as in Specification 545,679) or boron crystal or silver sulphide elements may be used. Specification 615,988 is referred to.