Transformer output test instrument - checks if output voltage is within preset tolerances by use of three meters in circuit with operational amplifiers

摘要

The test instrument is for the qualitative checking of deviations of a monitored A.C. voltage from its nominal value, with a first comparator detecting if the signal exceeds a predetermined limit, and a second comparator detecting if it falls below a second lower limit, and a pair of meters indicating such deviations. A third meter indicates that the signal voltage is within the limits. The input A.C. voltage may be fed to the indicating meters through rectifiers and operational amplifiers allowing comparison with a D.C. reference voltage. It is suitable esp. for production testing of precision instrument transformers.