High gain amplifier with current limited positive feedback

This invention relates to a high gain amplifier, and more particularly to such an amplifier which limits the current available when an intermediate stage is overdriven to positive feedback. A high gain amplifier includes an intermediate gain stage; an output gain stage driven by the intermediate gain stage; an input stage, for driving the intermediate gain stage, which is balanced between positive and negative feedback in normal operation; bias means for driving the input stage to maintain balance between positive and negative feedback in normal operation; and a resistance for limiting the output current of the intermediate stage in response to the input stage being overdriven into positive feedback.