› Forums › Focus Products › EEG Developer Kit › Electrodes output reaches up to 5V when they're held in the air. › Reply To: Electrodes output reaches up to 5V when they're held in the air.
Sorry for late reply. And thanks for using foc.us active electrodes.
I’ve edited links in your post and now pictures displayed correctly.
This behaviour is normal.
This is because input voltage at active electrode isn’t referenced to electrode’s ground now. Signal at electrode’s input must be in range from 0 to +V (electrode’s power). In EEG systems this is normally done using bias electrode, see Patient bias
8-12Hz filter can’t help you at this moment, because measurement taken incorrectly.
So, yes, you should connect the bias electrode to your body.
Also I suggest you to try to get ECG first. Amplitude of ECG is much higher comparing to EEG and it is easier to get because of this.