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SEQ-555ES
Making of divided voltage
47k
from IC5o,
Ei
(microcomputer D)
ICs10
Actual
separation
E/2
is by
resistor,
but
equivalently
it is by
battery.
In the above figure, a high or low signal is applied to
ICsi9 © pin from the microcomputer.
ICsi9
does switching operation, and output voltage
is as follows.
When E/2 is 0
e
E(5.6V)
5V
Ea
E/2(2.8V)
0
ov
E(5.6V)
—_—
E
4.2V
———-
2/3e
Eb
E/2(2.8V)
0
IV
———-2/3e
OV
E(5.6V)
3.4V
——_|/3e
Ec
E/2(2.8V)
:
2
—1/3e
OV
ICyo, (from microcomputer D)
switch signal
Es 4
switching signal
2/3E or —2/3E voltage
is constantly output.
OX
3X
OX
3x
OY
3Y
OY
3Y
ON
ON
ON
ON
e
Ye
A output voltage
~Ye
—e
B output voltage
we
—Nwe
Voltage as shown above is output in the A, B outputs,
A, B and C voltage and 1/2E voltage are applied to
the LCD unit and IC's.
The LCD display circuit is as follows.
O A voltage
O B voltage
When
the potential difference at the two LCD pins
is more than 1.5V, it lights up.
The following is for A voltage only.
E
E/2(0)
ok
Interval when C
1/2E interval
voltage is applied
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