Linear servo amplifiers are available with rated bipolar output currents from 25 to 200 ma. They may be operated both open loop or closed loop with a suitable feedback transducer. Open loop regulation is typically better than 1%, using the internal current feedback. Proportional or integral gain mode operation is standard. All models require a bipolar 10 to 30 volt dc power supply. The input and feedback command signals can be obtained either from a potentiometer or external voltage source. Provisions are included for an external dither signal. Models are available with or without acceleration and deceleration ramps. All models include bias and gain adjustment controls. The current limit is internally set to the rated maximum. These amplifiers are suitable for use with all servovalves and electrical displacement controllers with current requirements up to 200 ma.