This Aerospace Standard establishes the minimum sage performance standards for electrical type temperature instruments primarily for use with reciprocating engine powered transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in Section 3.4. This Aerospace Standard covers two basic types of temperature instruments as follows: TYPE I Radiometer type, actuated by changes in electrical resistance of a temperature sensing electrical resistance element; the resistance changes being obtained by temperature changes of the temperature sensing resistance element. TYPE II: Millivoltmeter type, operated and actuated by varying E.M.F. output of a thermocouple; the varying E.M.F. input to the instrument being obtained by temperature changes of the temperature sensing thermocouple.
SAE AS413B-1969 Referenced Document
SAE ARP582 Lighting, Integral, for Aircraft Instruments; Criteria for Design
SAE ARP798-1965 Design Criteria for White Incandescent Lighted Aerospace Instruments