Advanced auto-ranging, self-test and universal input power features are employed by Model AP-501 instrument to provide an accurate means of measuring roll and pitch information commonly available as synchro or resolver signals. This synchro/resolver angle position indicator automatically accepts resolver inputs of 2V to 32V or synchro inputs of 8V to 130V, 47 to 3000 Hz. Display resolution is ±0.01° and accuracy is ±0.03°.AP-501 also features a synthesized reference that automatically adjusts for rotor-to-stator phase shifts. Angles are shown on a five decade, 0.56" LED display. Selectable ranges extend from 0° to 359.99° or 0° ±180°. Built-in diagnostic circuits continuously monitor for loss of signal, reference and tracking.The tester accepts 85 to 265 vac, 47 to 440 Hz and comes in benchtop (3.25" x 8.83" x 7.84") and half-rack (1.75" x 9.50" x 7.63") models.