Complex sentence: The feedback amplifier also gets an input from the signal generator that determines the command potential, and it subtracts the membrane potential from the command potential (V command-V m), magnifies any difference, and sends an output to the current electrode.
Split into simpler sentences: The feedback amplifier also gets an input from the signal generator that determines the command potential, and it subtracts the membrane potential from the command potential (V command-V m). It then magnifies any difference, and sends an output to the current electrode.