Answer 1
The circuit below eliminates the leakage current through D2 by holding its anode at the same voltage as its cathode.

The leakage current through D1 is carried by the feedback resistor with negligible drop across the resistor. See The Art of Electronics (W. Hill and P. Horowitz, The Art of Electronics, 2nd edition, Cambridge University Press,1989.), section 4.15, for an in-depth analysis of this circuit.

Contributor: Dave Tweed

Published April 2003