abdoalghareeb
Member level 5
this is my design for Thermocouple K-type amplifier
The output (TC) of amplifier circuit is connected to ADC0 PORT of ATMEGA8L
At first : To calibrate the amplifire (LT1012) I remove the microcontroller then I short the Thermocouple input to ground , then I adjust the offset
potentiometer(R1) to make the output of amplifier circuit equal zero .
now I insert the microcontroller and the problem appears here , about 100 mv appears on ADC0 port (it should be stay zero).
Why does this millivolt appear?
![123.png 123.png](https://www.edaboard.com/data/attachments/78/78856-7c10fb1174fde839fa64467ec2525d43.jpg)
The output (TC) of amplifier circuit is connected to ADC0 PORT of ATMEGA8L
At first : To calibrate the amplifire (LT1012) I remove the microcontroller then I short the Thermocouple input to ground , then I adjust the offset
potentiometer(R1) to make the output of amplifier circuit equal zero .
now I insert the microcontroller and the problem appears here , about 100 mv appears on ADC0 port (it should be stay zero).
Why does this millivolt appear?
![123.png 123.png](https://www.edaboard.com/data/attachments/78/78856-7c10fb1174fde839fa64467ec2525d43.jpg)