Vacuum-Tube Tester
possible to apply any desired potential to
the grid of the tube. Binding posts, neatly positioned around three sides
of the panel, provide for the following: -- grid battery, grid voltmeter,
filament battery, filament connector, plate battery, plate voltmeter and
plate milliammeter. Complete as described, but without accessory measuring
instruments … $14.50” From the 1936 catalogue of the Central
Scientific Company.
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“Vacuum Tube Testing Outfit, Cenco “Visigram”
(Patent No. 1.968,039), designed to aid the elementary student in the usually
confusing study of a radio vacuum tube characteristics. Consists of a compact
assembly of tube socket, filament rheostat, potentiometer, reversing switch
and binding posts mounted on a panel 16 cm square supported about 6 cm above
the top of the table. The wire connections are beneath the panel, and are
open so that every detail may be examined by the student. The instructive
feature, making the unit such an invaluable piece of elementary laboratory
apparatus, is the detailed wiring diagram which is worked in with the controls
on the panel. At a glance the student can see what potential is on the grid,
how it may be reversed, whether all of the filament rheostat is in or out,
etc. The apparatus is designed for use with three electrode four-prong
tubes. The high resistance potentiometer, in connection with the reversing
switch, makes it |