Dynascan B&K 667 Buku Petunjuk - Halaman 9
Jelajahi secara online atau unduh pdf Buku Petunjuk untuk Peralatan Uji Dynascan B&K 667. Dynascan B&K 667 12 halaman. Solid state tube tester
Halaman CetakSELECTED
VOLTAGE
Sane
;
SELECTED
D.C. AMP
MES
ee
METER
RESISTOR
NN
FIGURE
3.
Cathode
Emission
Test
Testing Tubes
for Grid
Emission
and
Gas
Vhe
Grid
Emission
and
Gas
'Test
is
a
valuable
aid
in
'TV
servicing
because
it quickly
picks
out
those
tubes
which
can
cause
trouble
in a.g.c.,
syne,
LF. amplifier, and R.I*. tuner circuits.
In order to understand
how a tube can have "grid emission"
and "gas
current" we must look into the theory of electron tubes.
There is normally some gradual evaporation
of the electron emitting
material which the tube manufacturer applics to the cathode.
Some of this
vaporized
material
tends
to deposit on
the grid and
gives rise to what
is
known
as "grid emission",
where
the grid itself emits electrons and draws
current
commonly
known
as "negative
grid
current".
The
flow
of
this
"negative grid current" can be followed in Figure 4.
||
-
+
FIGURE
4.
Negative
Grid Current
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