A method for screening the Production Lots of ferrite cores to be tested for MTC is required because of testing limitations and large variations found between Production Lots. It is proposed that a sample of 100 cores be taken from each lot and tested at the factory. The mean of the sample must be between the Screening Limits specified for the lot to be accepted, from the manufacturer, for complete testing. The Per Cent Yield of the total number of cores to be tested individually has been calculated as a function of Screening Limits (see Figure l)
