Simpson 1000 - Special Applications

SPECIAL APPLICATIONS
nected to the #7 terminal of the tube socket. Set toggle
switch ‘‘G’’ at 1 to connect filament voltage. Set the FILA-
MENT switch at the rated voltage for the lamp to be tested.
Set the LINE ADJUSTMENT control to a position which
will cause the meter to indicate at the ADJ. LINE mark on
the scale. Insert the lamp in the receptacle and it will
light to its normal intensity if it is a good lamp.
DETERMINING TUBE ELEMENTS INVOLVED
IN A LEAKAGE PATH
The recommended short tests will indicate that there are,
or are not, satisfactory resistances between the elements
of any tube under test. To simplify these tests and shorten
the time required for testing each tube, the system recom-
mends isolation of alternate elements in the tube. This will
indicate when a leakage or short exists, but will not fur-
nish sufficient information to show you which elements are
involved.
Most indications show the combined resistance through two
parallel paths; for instance, when the cathode is separated
from the rest of the tube elements, any leakage resistance
between the cathode and filament is in parallel with any
leakage resistance between the cathode and the next ele-
ment in the tube--the plate in a diode or the control grid
in any other tube.
In some circuit applications, a lower-than-normal resis-
tance between cathode and control grid may allow satis-
factory service, while in another application, it may be
necessary to have more than 250,000 ohms between these
elements. Do not use a tube which has low resistance
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