Question

What does PTAT stand for?

Show the schematic for average temperature measurement using three AD592 sensors.

Show the schematic for average temperature measurement using three LM135 sensors

Answer 1

1. PTAT stands for Proportional to Absolute Temperature and is normally used to refer voltages or currents that increases proportionally with Temperature.

2. Given below is the circuit for temperature measurement using a single AD592.

To be able to find average for three such sensors we can place them in series. Since the same current is flowing through all the sensors the output voltage will be sum of voltage drop across individual sensors. The circuit is shown in figure below.

3. Given below is the schematic to get measurement from a single LM135 sensor.

To get the average value from three such sensors we can place them in series because the current through each sensor is constant the output voltage will be the sum of all three voltages. The circuit diagram is given below: