Agilent 1959-07 free download

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HEWLETT- PAC K ARD 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.10 No. 11-12 UBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA JULY- AUGUST, 1959 A Precision DC Vacuum -Tube Voltmeter with Extended Sensitivity and High Stability The increasing use of transistors and other 1 millivolt full scale to 1,000 volts full scale low- voltage devices has made the need for at an accuracy of ±1%. It also measures posi accurately determining low-level dc voltages tive or negative dc currents from 1 microam and currents a common problem. To meet this pere full scale to 1 ampere full scale with a need and to provide for increased accuracy in voltage drop on the sensitive ranges of only 1 making dc measurements in general, the new millivolt maximum. This range of voltage and dc vacuum-tube voltmeter shown below has current sensitivities thus substantially simpli been designed. Basically, this instrument is fies the matter of obtaining accurate informa characterized by a sensitivity 40 to 60 db higher tion in nearly any application involving tran than that usually associated with such instru sistors and in most applications involving vac ments, while its accuracy is such as to place it uum tubes. well within the precision category. At the same The general usability of the instrument is time the design has achieved very high stabil enhanced by a number of additional conven ity to enable it to monitor low-level values on iences. The instrument will directly measure a long-term basis and has avoided such com resistances over a range from 1 ohm center- mon inconveniences as a grounded terminal scale to 100 megohms center-scale. Output ter and extended warm-up drift. minals are provided to enable it to be used