HP AC-4A - AC-4 A Reset Circuits; AC-4 A Reset to Zero Circuit

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E. RESET CIRCUITS FOR USE WITH THE AC-4A
In automatic electronic counting equipment it is usually desirable
to reset the Decade Counters with an electrical pulse rather than
with a manual switch. The circuit in Fig. 8 will reset all AC-4A
Decade Counters to ZERO simultaneously if a positive pulse is
applied to the INPUT of the 2D21 Reset Thyratron. Depressing
the MANUAL RESET will also return all decade to ZERO.
47
INPUT 0-0------ill~-----A../\f\r----+-
_L_ Rl9
2MEG
-105
+200
6
.01
RESET PULSE
TO
AC-4A
( BASE Pl N 2)
_L_
470
MANUAL
RESET
Fig. 8. Circuit to Reset AC-4A Decade Counters to Zero
NOTE
A positive pulse at the input to this circuit delivers
a 150 volt positive reset pulse with fast rise and
slow fall to reset all AC-4.A Decade Counters to
ZERO simultaneously. This circuit will function
if Rl9 is removed and Rl8 is returned to approxi-
mately -30 volts. Smaller negative voltages than
-30 will enable the reset thyratron to be triggered
by a lower amplitude positive pulse but will also
make it more susceptible to stray pulses from
other circuits.
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