Indicator Circuit - Sharp R-8320E Service Manual

Method of Display
Indicator element is Fluorescent Display.
Basically, a Fluorescent Display is a triode having a cathode,
a grid and an anode. Usually, the cathode of Fluorescent
Display is directly heated and the filament serves as cathode.
When a proper voltage is impressed to the filament to heat
it, thermo-electrons are emitted and, with positive voltage
with respect to filament being applied to the anode and grid.
hit against the anode to illuminate the fluorescent body.
If the anode or grid voltage is zero or negative against the
filament, thermo-electrons can not reach the anode, hence
the fluorescent body is not luminescent.
CIRCUIT
INDICATOR
In this model, the Fluorescent Display g-digits, 7-segments
are used for displaying figures, 6-segments are used for
Convection Fan Symbol and letters.
The Fluorescent Display employs the dynamic drive
method, when the high level of anode signal and grid signal
agree, the corresponding segment displays.
Figure 24. Indicator Circuit
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