The Analogic model AN2574 is a high accuracy, high performance 4½ digit (±19999 counts) digital panel instrument. Features such as a gigaohm differential input, microvolt sensitivity, and programmable TRI-STATE BCD outputs, place this high quality precision instrument into a class by itself. Three power options including 110VAC, 220VAC and +5VDC, and fullscale ranges o f ±1.9999 Volts or ±199.99mV make the AN2574 universally applicable. Instrumentation features include a unique, guarded and isolated analog front end with common mode rejection ratios (CMRR) as high as 140dB, an auto-zeroed input circuit for long-term stability, FET input circuitry with low (picoAmp) input bias current and high (gigaohm) input resistance, and an optimized signal-enhancement filter which maximizes rejection of normal mode interference signals while providing input over-voltage protection of more than 100V. Serial and word-programmable TRI-STATE BCD outputs provide the utmost versatility and satisfy virtually all instrumentation requirements. The displays are designed for maximum readability. Up close, several feet away, or off at an angle, the five large (.43") red LED digits are bright, clear, crisp and free from glare and interpretation problems even under high ambient light conditions. When an input overload condition occurs, all five digits are automatically blanked to prevent an erroneous reading; however, the polarity sign and decimal point remain displayed to show that the instrument is working properly.