Quote Originally Posted by dr bob
You are correct that bridge circuites require a minimum current for operation. However at null that current flows equally through both legs of the bridge.
I am having trouble convincing myself. I think there will be 15% greater current through the meter with the Ag cells. So the meter should read slightly higher. Maybe setting the meter's hairspring tension to center at 3.4ua would work. In short, why is the meter current not linearly dependent on the supply voltage?