Temperature Sensing and Control

This is a temperature indication and control system using the AD596/AD597. In this system, AD596/AD597 is used as a closed-loop thermocouple signal conditioner. This system uses an external op amp to implement setpoint. The advantages of this system are preserves the alarm function for open thermocouples and provides a high level (10mV/°C) output for the A/D panel meter. Here is […]

Read more

Simple Temperature Controller

This temperature controller employs an LM135/235/335 temperature sensor, can be used to keep small environment warm or hot. Here is the schematic diagram: LM311 is used as comparator, to detect if the voltage at sensor pin (the inverting input) goes higher than the reference pin (the non-inverting pin). If this condition is detected, the comparator will switch off the heater […]

Read more

4mA–20mA Loop Powered Temperature Sensor

This circuit is used to allow  a 4mA–20mA to power an analog temperature sensor. To provide a 4mA–20mA output over a 3.75V–28V compliance range this circuit uses an op-amp, low-dropout linear regulator, transistor and an analog temperature sensor. It  is powered by the loop with the only consequence being a slight offset error because of the quiescent current of the […]

Read more
1 2