1192 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1956 



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Fig. 10 — Details of modified microfarad meter. 



CAPACITANCE TEST CIRCUIT OPERATION 



The wide range of capacitance values to be measured, both with and 

 without the series resistance in resistance-capacitance networks, and the 

 one and two-unit construction of the product imposed limitations on the 

 type of capacitance measuring circuits that could be used in this ma- 

 chine. The method selected consists of modified Weston Model 372 

 microfarad meters that automatically set up external circuits associated 

 with the meters to accept or reject the product as determined by limits 

 preset into the machine. 



Two decade capacitance boxes, having a range from 0.001 to 1.0 mf 

 in steps of 0.001 mf are connected in series or parallel with the capacitoi' 

 on test to make the resultant capacitance fit the range of the meter and 

 control the maximum and minimum limits. This procedure increases the 

 number of capacitor codes that may be tested on a given meter. Capaci- 



