The Model 5113 Low-Noise Preamplifier provides high gain, low-noise amplification of wideband signals from DC to 1 MHz, well suited for use with both SIGNAL RECOVERY and other manufacturers’ signal processing instruments. Adjustable high and low frequency rolloffs allow the bandwidth to be reduced. Two inputs, with switchable coupling, allow either differential or single-ended operation. Coarse gain is selectable from x5 to x50,000 in a 1-2-5 sequence with a fine gain control extending the range to xl to X 10,000. An uncalibrated vernier allows finer adjustment of the gain. The unit may be powered either from an external DC power supply or from its internal sealed and maintenance-free lead-acid batteries. These batteries recharge automatically when a suitable external power supply is connected. Other features include an overload fast-recovery button, a front-panel DC zero screwdriver control, and a battery test facility.