What is connected to the RA and LA inputs?
RA - Right Arm
LA - Left Arm
I'm trying to implement a eletrocardiogram
What is the voltage of the RA and LA inputs?
The differential amplifier consisting of opamp_1 and opamp_2 amplifies the voltage difference of the RA and LA inputs. If the difference is too big the output of opamps will be saturated.
The DC potential of the positive input of the opamp_4 is zero volt. Any bias voltage is required at the input because the opamp_4 is used as a non-inverting amplifier.
I recommend to use a differential input of the ADC. Please refer following code example and documents.
CE95272 - PSoC® 4 SAR ADC and Differential Amplifier