Circuit Description — Type
3A74
tNPUT
INPUT
DIODE
OUTPUT
AMPLIFIER
-- CE
i
—ameLiFieR —|
switches
— "|*—
IST STAGE
+18.5V
wet eneer ey
=3.3ma
BUSSES CONNECTING
R444
SWITCHED
AMPLIFIERS
<
TO OUTPUT AMPLIFIER
SIGNAL OUT
Xr
.——_
To peiver
EF
D440
Q444
R424
22.5
_
WAY
ma
12,.8V
Dh
4
Q424
~12.4V
el.3ma
=3.8
$ 7.1ma
+300V
mai
§
OFF
hf D441
Ne
'\
EFFECTIVELY
GAIN
+125V
12.4% EACH
=3.8ma
>
4
R438
~3.8ma
l
|
D443
Dis
~12.8V
=3.BM4
§
R434
22.5 ma
MAA
Q 454
SIGNAL
OUT
To DRIVER
EF
R454
LOCATED IN
RING COUNTER |
+ aE SouaPLEMENTARY
+18.5V
CURRENT
NOTE:
THICKNESS
OF
THE
HEAVY
BLACK
LINES
1S
SOMEWHAT
PROPORTIONAL
TO
THE
CURRENT
FLOWING
IN
THAT
LINE.
NO
SIGNAL
1S
APPLIED
TO
THE
CHANNEL.
Fig.
4-2.
Simplified circuit diagram showing the dc current paths when channel 1 is turned OFF.
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