Advertisement
100
T Y P E
6 0 3
E L E C T R O N I C
M U L T I P L I E R
The purpose of the capacitor C1 tied between
R2
and
R 3
to ground is to b ~ - ~ a s s
any stray pulses
on the line to ground and thus prevent them from
turning the trigger
ON.
Before rhe effect of a
pulse can be felt ar
G,
the capacitor C1 must be
charged, because during the charging time of C1
it is effectively a shunt to ground.
This means
thax any short duration transients will be dissipated
in charging C1. The exact time constant is deter-
mined by the value of
R 2
and C1. Of course, this
produces a slight delay in the triggering operation
when a brush makes, but the delay is not objec-
tionable because the brush contact duration is con-
siderably longer than required to turn the trigger
O N .
The purpose of the KC combination RI-CR4 is
to ground the CB's between pulses and thus pre-
vent unstable operation resulting from "floating"
lines when the CB's are open. The purpose of the
resistor Rs in the screen and suppressor circuixs of
the 6SK7 is to prevent parasitic oscillations. The
screen resistor also presents a means of producing
equal current flow through all tubes used in paral-
lel.
For example, one tube's characteristic may
post I
be such that its screen and anode current during
conduction are higher than the screen and anode
current of orher tubes. When all tubes are oper-
ated at the same voltage, the higher screen current
of this tube will cause a greater voltage drop across
the individual screen resistor for this tube and will
xhereby reduce the screen potential, resulting in a
decreased anode current. Thus, variations in tube
characteristics produce no variation in operation.
Read-In Pulse Circuit
The block diagram in Figure 95 indicates that
the 9 pulses provided to control reading into a
counter are directly from a CB cam contact.
Actually, this is not true, because a cam contact
is likely to be erratic because of contact bounce,
and several pulses may be entered in a counter for
one cycle point. T o avoid this trouble,
he
CB's
control a trigger which in turn controls a power
tube to ~ r o v i d e the pulses to control the read-in
switch pentodes.
A
power tube is necessary be-
cause if a ,trigger is loaded, unstable operation re-
sults.
Mid-index
Index- line
pulses
pulses
1
-
- 1 0 0
A l l resistance values in mepohms
(Cancel)
Figure 97. Read-in Pulse Circuit
Advertisement
