A high-speed microcurrent amplifier

By the use of feedback amplifier techniques considerable improvement has been made in the speed and/or stability of the familiar electrometer tube micromicroammeter. Simplicity and compactness have been retained. With 100 feet of input cable, the amplifier has a 150-millisecond time constant at
^{10 ¯11 amperes full scale with 0.05% per day stability.}