RESPONSE TIME OF AND EFFECTS OF RADIATION ON THE VECO BEAD THERMISTOR

Experimental tests were performed on VECO bead thermistors coated with Krylon Glossy White No. 1501 Spray Enamel, carbon black, and aluminum. Tests were run in an environmental testing chamber at pressures of 670, 87, 8, and 1 mm Hg, corresponding to altitudes of 4,000, 50,000, 100,000, and 150,000 ft respectively. Temperatures were varied between +20C and -70C at each of the above pressures, reproducing as nearly as possible the environmental conditions expected during the descent of a parachute-supported temperature telemetry system. It was found, however, that radiation from the walls of the test chamber prevented the thermistor from reaching an equilibrium temperature with the surrounding air. Thermocouples placed within the test chamber to monitor the temperature of the air behaved in the same way, i.e., failed to reach equilibrium temperature with the air. To determine the air temperature, an acoustic thermometer was devised. Air was circulated in the chamber at a velocity of 132 ft/min during the tests. This velocity was determined at 670 mm Hg. Includes Supplement No. 1, Aug 1961.