AD590 based Temperature Sensor

 Opamp-Circuits  No Responses »
Jan 162005
 
AD590 based Temperature Sensor

The voltage at the point 1 of R4 will be :Vo=( 1+ ( 10K/22K)) * Vref = 3.63V as nominal Vref is 2.5V.AD590 is a current source which gives 1 uA / kelvin, It is independent of the voltage across the device. you can treat it like a current source or sink or impedance. total voltage across AD590 is 5V as opamp pin 2 is at virtual ground. This is the way you try to understand the design. The AD590, here is a constant current sink as cathode goes to -5. The current it sucks away or drains from node Read More …

 Posted by admin at 11:34 AM  Tagged with:

Thermocouple Amplifier Standard

 Opamp-Circuits  No Responses »
Jan 142005
 
Thermocouple Amplifier Standard

The OP07 is a low offset 75uV opamp, here it is used to amplify the output of a Thermocouple, the gain of this stage is high. The zeners are to protect any high voltage at input zapping the opamp. The Resistor R6 limits the current. The zeners should be low leakage or use clamping pull-up and pull-down diodes to +5 and -5 respectively. The RC low-pass filter formed by R6 and C2 reduce the mains hum or 50 Hz pickup of long thermocouple cables laid close to high current heater wiring. R1 is a offset null use or add if Read More …

 Posted by admin at 3:12 AM  Tagged with:
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