Carries AC waveform Superimposed on DC. Application is to provide AC waveforms to Arduino Analog Input (0-5VDC).
The 1MOhm resistor represents the Analog Input. The AC supply represents the attenuated test signal. The POT connected to DC supply sets the superimposed offset. The POT connected to the AC test signal sets the gain. The 5V Zener Diode is present for accidental overvoltage protection to the Analog Input. Reverse polarity protection is not needed as the OpAmp Vin references 0V, not a virtual ground.
