Voltmeter and Attenuators in Combining Case
Accession Number: 2014.ep.19
The instrument consists of three analog electronic devices in a combining case. The case is made of aluminum, and is painted gray on its top, bottom, and side faces. These faces have a faux leather texture. The rear face of the case has machined opening, and a small label centered at the top. The bottom face has four black plastic feet. The electronic devices are arranged in the case from left to right as follows: an attenuator, a voltmeter, and an attenuator.
The three devices have labeled black plastic knobs and dials. The faces of the attenuators are identical, and have input and output connection points with black and red plastic covers. The face of the voltmeter has a two-position switch, an analog dial readout, a bulb with a red plastic cover, and an uncovered metal connection point. The three devices are separated by aluminum plates, with a plastic strip separating the devices’ faces.
Primary Materials: Aluminum, plastic.
On both attenuators, there are markings in black ink around a dial reading “DB” and the numbers 1-10. There are also markings in black ink around another dial reading “DB” and the numbers 0-100, in steps of ten. Above the plastic covered connection points, there are markings in black ink reading “INPUT”, “OUTPUT”, and the conventional sign for earth-ground (⏚). Underneath one of the dials one both attenuators is a marking in black ink reading “350D ATTENUATOR SET 5W-55V 600Ω DC-IMC”. Underneath this marking is another marking in black ink reading “HEWLETT PACKARD”, with the company logo in black ink separating the words.
On the voltmeter, there are markings in black ink around a dial, reading “RANGE”, and in duplicate on the left and right of the dial “VOLTS” and “DB”. On the left side under “DB” are the numbers -10 to -60, in steps of 10. On the left side under “VOLTS” are the numbers .3, .1, .03, .01, .003, .001. On the left side under “DB” are the numbers 0 to +50, in, in steps of 10. On the left side under “VOLTS” are the numbers 1, 3, 10, 30, 100, and 300. Above the two-way switch is a marking in black ink reading “ON”. Above the red bulb cover is a marking reading “LINE”. Under the analog dial readout is a marking in black ink reading “3400A RMS VOLTMETER HEWLETT-PACKARD”. To the left of the marking is the company logo in blue ink. The dial readout is marked “DECIBELS 1MW 600Ω”, “R.M.S. VOLTS”, and has the company logo underneath. The rear of the attenuator is marked “U.S. PAT. PENDING 528-05828 115/230 VOLTS 50-1000 CYCLES MADE IN U.S.A.” and “ACCURACY 10 Hz 50 Hz 1 MHz 3 MHz 10 MHz ± 5% ± 1% ± 2% ± 3% ± 5% ACCURACY % FULL SCALE CREST FACTOR 10:1 AT FULL SCALE INPUT IMPEDANCE 1mV to 300mV RANGES – 10M//40pF 1V to 300V RANGES – 10M//15pF” and “D.C. OUT 115 V/230V/.25A”
The rear of the combining case has a plate marked “COMBINING CASE MODEL 1051A HEWLETT PACKARD MADE IN U.S.A”.
Width = 49 cm, Length = 34 cm, Height = 19 cm
Good: The artefact exhibits no damage or significant wear, aside from the center knob which is cracked at the top right side.
Manufacturer: Hewlett Packard
Date of Manufacture: 1960s
Acquired from Paul Milgram’s Engineering Psychology laboratory.