Analog Temperature Sensor - AD592 Analog Temperature Sensor - AD592 - PowerPoint PPT Presentation

Analog Temperature Sensor - AD592 Analog Temperature Sensor - AD592 � Continuous signal (µA) proportional to temperature. � 1 µA ~ 1 K, so 293 µA ~ 293 K (20 C) � Current source � The digital DS1620 contains analog components.

Transducer Response Transducer Response � Low 5 � Rctime 5, 0, rct � Voltage at P5 rises from 0 V to ~1.4 V. � Temp (K) = Constant / rct 5 V � Temp , Current � Charge Time P5 � Automatic calibration 0.22 100 � � F 0 V

Resistance & Resistivity, ρ ρ ρ ρ Resistance & Resistivity, ρ ρ ρ ρ � Resistance is the opposition to current flow. � In a conductor, R = ρ ρ x Length / Area ρ ρ � Different materials have different resistivities. � Generally, ρ ρ is temperature dependent. ρ ρ � Temp , ρ ρ ρ ρ

Conductance,G & Resistance,R Conductance,G & Resistance,R � V=RI and I=GV, so G=1/R � Conductance = reciprocal of resistance. � Units of G = Siemens (S) � Conductance is a measure of how easily current can flow.

Series Resistors, R1 & R2 Series Resistors, R1 & R2 = + Req R1 R 2 − − − = + 1 1 1 Geq (G1 G2 )

Resistors R1 & R2 in Parallel Resistors R1 & R2 in Parallel − − − = + 1 1 1 Req (R1 R 2 ) = + Geq G1 G2