The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1924-04-15

this IS Drought about, there is
maximum transfer of energy from
the primary to the secondary and
with loose coupling Ccoils separately
there is q maximum transfer OF
energy on the wave length the
coils are adjusted to and inter.
ference not on. that wave length
has little chance of getting from
one coil to the other ass
One OF Best Features.
This is one of the best features
of an inductively coupled set Zone
cults are not directly connected.)
The single circuit set is the most
popular type today, but due to its
defects in being unable to eliminate
interference, it will have to- give
way to the coupled circuit receiving
set. While the wave trap helps
the single circuit set, 1t only shuts
out one interfering wave at q time.
Figure illustrates variometer,
which is two coils of wire in series,
one within the other. II turned end
to end so that one winding runs In
opposite direction to the other and
current Of radio frequency is
flowing through them due to the di-
rection of the lines Of force, there
will be opposing fields created and
their mutual induction Is zero. With
this coupling. the variometer re-
spends to low wave lengths. If the
movable coil is rotated SO that
their fields be additive. the two
fields will act with each other and
the mutual induction will be maxi
mum. This gives you the longest
wave length the variometer is cap
able of being adjusted to. BY slow
ly moving the variometer between
the first position and the last, the
variometer may be used for tuning,
covering a. low to a high wave
length. Vafiometers can be used as
primary coils and also to, adjust
the secondary circuit by being in
series with. the secondary coil. or
can be used for regeneration by be-
ing in the plate circuit.
Loose VariO Coupler.
Figure 2 is that of a loose or
vario-coupler,' one coil being within
the other similar to variometer,
but differ in that the two coils are
not directly connected. They are
used as the primary and secondary
in loose coupled set and as the
primary and ticker coil, in a single
circuit regenerative set. II the
rotor coil is turned so as to be end
to end as shown.in Al, the magnetic
field surrounding the primary will
envelope the secondary, passing
through 1t and causing a current to
flow through the secondary coil.
II the secondary. coil is placed at
right angles to- the primary as
shows at B. there will be little cur
rent induced in 1t as the lines of
force from the primary coil only af.
fect part Of the rotating COIL while
II the coil is moved still farther as
shown at c, the current induced in
the second coil will flow In the op-
posite direction and reaction be.
tween the two coils is nil. This is
what happens when your single
circuit regenerative set does not re.
generate or oscillate. All that is
then necessary Is to reverse the
leads to the ticker coil and this
changes the direction OF current
The degree of angie or counting
between the two coils is what de.
termines the transfer OF energy be-
tween them and 1t, Is with careful
manipulation of. these coils that
best results are obtained from your
set. ON q loose coupled two
circuit set, the greater the .h2le
hetweeEl. the primary andeseconTary
coils. the less interference you will
pick up and the sharper will be the
tuning &