Ive been studying instrument amps and filters. I found this schematic online of a single channel eeg and am alittle confused on what the third electrode (very bottom left of schematic) is actually connected to. I know the electrodes that are hooked up to the noninverting and inverting of the instrument amp are grounded to vcc/2. But the schematic is alittle confusing on the third electrode(very bottom left of schematic), is this hooked up to the OV of the 9V supply or vcc/2?. As of right now im more concerned with just hooking everything up. Later on, I plan on playing with the values for my bandpass filter, and then hooking this all up to an Arduino.Any help would be great. Thanks.
https://backyardbrains.com/products/files/EMGSpikerShield.v.1.1.pdf
https://backyardbrains.com/products/files/EMGSpikerShield.v.1.1.pdf
