Agilent 1958-06 free download

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HEWLETT-PACKARD JOURNAL T E C H N I C A L I N F O R M A T I O N F R O M T H E - h p - L A B O R A T O R I E S Vol.9 No. 10-1 PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA JUNE-JULY, 1958 A Clip-On DC Milliammeter For Measuring Tube And Transistor Circuit Currents IN typical electronics work direct currents in practice often results in omission of the are ordinarily measured either by measur measurement with subsequent erroneous de ing the current directly with a moving-coil duction and wasted effort. Additionally, in type current meter or by measuring the volt the continually-growing field of low- imped age drop across a known resistance in the ance circuits, where the current parameter circuit. Although each of these methods has assumes greater importance as in transistor a long tradition, each also has substantial work, the resistance of the moving-coil in disadvantages. In the case of the indirect strument is sometimes intolerable. method with a voltmeter, the A new and much-easier-to-use current- measurements are most often measuring instrument that overcomes the made across resistances hav foregoing objections has been developed in ing tolerances of 10% to 20% so that a mini the form of a clip-on dc milliammeter which, mum ambiguity of this same amount also as far as is known, is the first instrument of exists in the current value obtained. Fre