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78
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
Figure 74. Practical Eccles- Jordan Trigger Circuit
similarly coupled to the anode of T2. The resistors
R L are the anode load resistors while the grid bias
is normally furnished through the grid resistors
Rg. The values of RL, Rc, and R g are not critical
as to ,their exact value but
it is essential that the
circxit be sym?~zetrical.
R c and R g must be
matched within 2':L and they should be approxi-
mately ten times as large as
RL.
The value of C
determines ,to a great extent the speed of response
of the trigger circuit t o an applied pulse.
A suitable voltage pulse applied at the proper
points causes the conducting tube to stop conduct-
ing and the non-conductive tube to start conduct-
ing. A second pulse restores the original condition.
This cycle may be repeated at will at any speed
from zero up to speeds in the low radio-frequency
range, depending upon the circuit constants used.
Thc tubes used in the circuits illustra,ted in Fig-
ure 73 are 6JY's or the equivalent. The two triodes
can just as well be the t w o halves of a twin triode.
Figure 74 shows the Eccles-Jordan trigger cir-
cuit in a form more suitable for analysis. A close
study of Figure 74 will reveal that it is the same
circuir as Figure 73 with only the input circuit
added. The resistance and capacitance values shown
in this figure are the values used in the actual
triggers in the electronic computing circuits:
I n
this illustration the two triodes are the t w o halves
of a twin triode, Type 6SN7.
Figure
75
shows how T 2 can control T I .
As-
suming that both tubes are non-conducting, ,the
potential at the grid of T I can be determined by
the ratio of the resistors between t h e +IYO volt
line and the -100 volt line, or by determining the
current flow and computing the I R drop across
each resistor.
I n this manner the potential at G I
is found to be
+
19 volts; or 19 volts positive with
.""
-
.-..
Figure 75. Anode o f T2 Controls Grid o f T
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