(2) The currents continue to the right in the metallic wires of the line of side circuit No. 1 and join at the center
terminal of the secondary of RC2 (broken arrows). Since the current in the top wire flows down through the upper
winding, however, while an equal current in the bottom wire flows up through the lower winding of the secondary, the
same canceling effect occurs as in RC1. Therefore, no corresponding current flows in the primary of RC2 or in the
receiver of T2.
(3) The combined current flows out of the center terminal of RC2 and down through the secondary of RC6
(broken arrow). This is the same total current that flows up through the secondary of RC5. A corresponding current
therefore flows in the primary of RC6 and through the receiver of set T6, reproducing the sound originally introduced at
the transmitter of T5.
(4) By a similar analysis, the path of current can be traced through the secondary of RC4, the wires of the line of
side circuit No. 2, and the secondary of RC3. Since the same canceling occurs in these repeating coils, no phantom circuit
current flows in the primaries of these coils or in sets T4 and T3.
b. Path of side-circuit current.
(1) The use of repeating coils in a phantom group also prevents the side-circuit currents from interfering with
those of the phantom circuit. This can be seen by following the solid-line arrows from set T1 through side circuit No. 1
and set T2, and back again, to T1 (fig. 70). Assume an instant of time when a voice current originating in the transmitter
of T1 flows up through the primary of RC1. An emf is induced in the secondary, causing a corresponding current to flow
down through the entire secondary. None of this current flows out through the center terminal of RC1, and consequently
no part of the current flow through the secondary of RC5 or RC3. No interference exists, therefore, between set T1 and
sets T5 and T3.
(2) The current flows to the right through the bottom wire of side circuit No. 1 and up through the secondary of
RC2, the path being completed through the top wire. Again, no part of this current flows out of the center terminal of
RC2 or through the secondaries of RC6 and RC4. Therefore, no corresponding current flows through the receivers of sets
T6 and T4, and there is no interference in these sets.
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