True RootMean Square Voltmeter
Inventory NumberWJ0375
ClassificationVoltmeter
Subject
Maker
Ballantine Laboratories, Inc.
1934-present
Place of Origin
Dimensions31.8 x 48.3 x 27.9 cm (12 1/2 x 19 x 11 in.)
Signedon face of scale, very top: WESTON ELEC. CORP., NEWARK, N.J., U.S.A.
on face of scale, bottom center: (BL logo) BALLANTINE LABORATORIES, INC. / TO CHECK CALIBRATION / SET RANGE SWITCH ON 3.2. MV, 100 MV, 3.2 V OR 100 V RANGE. / SWITCH TO CAL. ADJUST CAL. ADJ. FOR 10DB READING / SET RANGE SWITCH ON NEXT HIGHER RANGE. / ADJUST METER SCREW FOR O DB READING.
on plate on top: TRUE ROOT-MEAN-SQUARE VOLTMETER / MODEL NO. 320 SERIAL NO. 1088 / 5 C.P.S. TO 500,000 C.P.S. / 200 MICROVOLTS TO 320 VOLTS R.M.S. / INPUT RESISTANCE 10 MEGAOHMS SHUNTED BY / 25 (greek letter mu)(greek letter mu)F. BELOW 10 MV. AND 8 (greek letter mu) (greek letter mu) F. ABOVE 10 MV. / MADE BY BALLANTINE LABORATORIES, INC. / BOONTON, N.J., U.S.A.
Inscribedin yellow on face, left and on top: RESEARCH LABORATORY / OF ELECTRONICS / USAF
in yellow on face, center: 7494 6
Ballantine Laboratories, Inc.
Date: 1947-1960
Accessories: one small plastic card: "Use the Ballantine voltmeter. . .".
Object number: 2006-1-0065
Ballantine Laboratories, Inc.
Date: copyright 1953
Accessories: "The Ballantine Rule," see 1998-1-1372a
Object number: 1998-1-1372b
Ballantine Laboratories, Inc.
Date: copyright 1953
Accessories: Instruction booklet, see 1998-1-1372b
Object number: 1998-1-1372a
Cruft Laboratory, Harvard University
Accessories: Loose vacuum tube in side.
Object number: RS1134
Allen B. Du Mont Laboratories, Inc
Date: 1950-1960
Accessories: laboratory notes (in CHSI library)
Object number: 1997-1-0489
Wang Laboratories, Inc.
Date: 1970
Accessories: cloth instrument cover lined with tissue paper; black power cord; accompanied by central electronic unit (2001-1-003b); two page hand-written note from Peter L. Smith, Research associate, Harvard College Observatory, regarding the donation of the calculator, dated 10 December, 2001 (original and copy in instrument file); photocopy of operation instructions from the bottom panel of calculator unit (in instrument file); printed document on the history of the Wang 360SE by Rick Bensene (in instrument file); printed document on the history of the Want 360SE from Geocity (in instrument file); printed document on the Orbiting Solar Observatories (in instrument file)
Object number: 2001-1-0033a