Power Consumption Form

Subsystem	Thermal
Author	Arnold Young & Sarah Brennan
Original Date	2/12/98
Last Review	3/13/98
Relevant Specs	R_sensor = 46.6k from measurements I_allowed = 5mA => P_allowed = (0.005²)(46.6k) = 1.17 W
Specs Source	LM335Z data sheet
Assumptions Made	The sensor obeys Ohm's Law, V = IR, so that the power is equal to V²/R.
Calculations/Method of Measurement	Worst case: +5V across sensor I_sensor = V/R_sensor = 5V/46.6k = 0.107 mA < allowed => P = V²/R = 25/46.6e3 = 0.536 mW With resistor: I = 5V/(4.7k + 46.6k) = 0.09747 mA => P = I²*R_sensor = 4.4e-4 W
Results	P = 0.536 mW (worst case) P = 0.443 mW (with resistor)