A microcontroller for temperature limit control has a 0 V to 5 V
power supply. An NTC temperature sensor provides an input voltage
to a ・} 5 V comparator op-amp. Depending upon whether the
temperature is below or above the set limit, the output from the opamp
comparator will be low or high. It is undesirable for a direct
electrical connection to exist between the sensor and the controller.
Draw a circuit diagram to show how you could interface the NTC
sensor to the microcontroller. Resistor values are not required.
The Attempt at a Solution
I have a diagram of a window comparator circuit (see attached) with the thermistors output being one of the opamp inputs. I think I could use a optics to transfer the signal from the comparator to the microprocessor. I was thinking of a LED to transmit the signal and a photodiode to receive it at the microprocessor, but I'm unsure how to draw this. Any help would be greatly appreciated.