ELECTRONIC TESTING INSTRUMENTS FOR INDICATING, CONTROLLING AND MONITORING-NAMELY, CALIBRATORS, SQUARE ROOT EXTRACTORS, MONITOR SWITCHES, SIGNAL ISOLATORS, SIGNAL LIMITERS, MULTIPLIER/DIVIDERS, ADDER/SUBTRACTORS, INTEGRATORS, MULTI-LOOP POWER SUPPLIERS, MILLIVOLT-TO-CURRENT TRANSMITTERS, VERTICAL SCALE INDICATING RATIO STATIONS, DEVIATION INDICATING CONTROL STATIONS, MANUAL CONTROL STATIONS, INDICATORS, RECORDERS AND TREND RECORDERS, COMPUTER MANUAL AUTOMATIC DIRECT DIGITAL CONTROL STATIONS, A...