Testing of Metallic Cores
Hughes, Arthur D.
Of 668 metallic cores tested, 38.8 percent were selected as good cores. The specification for a good core were: (1) an absence of disturb sensitivity,* (2) a switching time of 7.6 to 9.3 microseconds and (3) a disturbed-one voltage of 30 to 38 millivolts. Recommendations for future tests are made as follows: (1) obtain continuous calibration of oscilloscope and pre-amp with a standard known waveform superimposed on test scope screen; (2) obtain continuous calibration of driving current with a small current calibrator; (3) test cores in batches of approximately 24, tagging each batch and numbering cores in a predefined manner, eliminating color coding.