Text preview for : 1959-01.pdf part of Agilent 1959-01 Agilent journals 1959-01.pdf
Back to : 1959-01.pdf | Home
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. 5
PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA JAN., 1959
A New Digital DC Voltmeter
with Automatic Range and Polarity Selection
THE illustration below shows a new digi recorder combination is used. Function cod
tal dc voltmeter that automatically and ing, polarity and decimal location can all be
rapidly measures positive or negative dc volt included in the printed record.
ages anywhere within the range from 1 milli Electrically, the new voltmeter has a cali
volt to 999 volts and displays the measured bration accuracy of ±0.2% and in other re
value, including polarity and decimal point, spects has the supporting characteristics nec
in large illuminated digits. The instrument essary for accurate measurements in a wide
thus considerably facilitates situations such range of applications. It has a high input im
as equipment performance testing and pro pedance of 1 1 megohms, and its input circuit
duction work where simplicity, speed and is floating so that it can measure voltage
accuracy in making dc measurements are sources that are up to ±500 volts off ground.
important. Overload protection is also provided. Hum
The instrument also permits automatic rejection is 50 db or more with the result that
logging of measurements, since it is designed hum peaks as large as Va of the dc in a circuit
to directly drive the -hp- high-speed digital being measured cause an effect of only ±1
recorder to produce printed records of meas count in the least place of the readout. The
urements. Fig. 4 (page 3) indicates the type instrument includes a self-check feature such
of print-out obtained when the voltmeter- that accuracy can be tested at any time by