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Патент USA US2408194

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I Sept. 24, 1946.
H_ 5 BEST];
Filed Dec. 6, 1943
Patented Sept. 24, 1946
Harold Edward Beste, East Rutherford, N. J ., as
signor to Allen B. Du Mont Laboratories, Inc.,
Passaic, N. J., a corporation of Delaware
Application December 6, 1943, Serial No. 513,136
‘4 Claims. (01. 172—-246)
This invention relates to a phase shifter which
comprises a transformer of which the primary
is in the cathode circuit of a vacuum tube.
The invention may be understood from the
are of the same frequency as those in coil 6 but
of opposite polarity thereto or 180° di?erent from
coil 6 in phase.
The phase of the voltages applied to the con
description in connection with the accompanying
denser l3 and therefore to the control grid of
drawing, in which reference character I indicates
tube l5 depends upon the relative impedances of
a connection from a source of alternating cur
the condenser I 2 and the portion of resistance II
rent which may, for example, be of a frequency
that is in series across the secondary 8, 9 of the
of 100 c. p. s. The terminal 1 is coupled by
transformer ‘I. When the contact II’ is at the
condenser 2 to the grid of triode 3 which has 10 lower end of resistance II, the voltage at the
grid leak '4. The cathode 5 of tube 3 is con
grid of tube I5 is approximately90° ahead of
nected to one end of the primary 6 of transformer
that across the secondary 8, 9, and the more of
‘l, the other end of, which is grounded.
the resistance II that is placed in the circuit
Two like coils 8 and 9 connected in series and
by moving contact ll’ closer to the upper end
grounded ‘at the center it constitute the sec 15 of resistance II the nearer the voltage at the
ondary of the transformer ‘l. The lower end
grid of tube I5 is in phase with the voltage across
of the secondary i9 is connected to one end of a '
the secondary 8, 9.
variable resistance H, and the upper end of the
The current through the coil 6 is not depend
coil 8 is coupled by condenser IE to the upper
ent upon the phase or amount of current through
end of resistance II. A sliding contact II’ is 20 the coils-8 and 9, as this current depends pri
provided to vary the portion of the resistance H
marily upon the voltages at the grid and plate
7 that is in the circuit.
of tube 3.
A condenser 13 couples the phase shifter
Due to the comparative low impedance and
through resistance Id to the control grid of tri
high current in coil 6, any change in phase due
ode l5, this grid being provided With a grid leak 25 to adjustment of contact l I’ results in very little,
IE’ to ground. The cathode of tube I5 is con
if any, change in voltage output of this phase
nected to the cathode of tube l6, and both are
connected to ground through resistance IT. A
What is claimed is:
lead 18 extends from a source of positive potential
1. In an electronic device for shifting the phase
through load resistances l9 and 20 to the plates
of voltage, a vacuum tube to the control grid of
of the tubes l5 and I5. And this lead I 8 is also
which said voltage is to be applied, and a trans
connected through resistance 2| to the screen
former having its primary ‘connected between
grids of the tubes l5 and H5 in the usual way.
The tubes l5 and I6 and connections consti
tute or provide a balanced phase-inverter de?ec
tion ampli?er, from which signals of opposite
polarity can be taken and coupled by condensers
the cathode of said tube and ground, the ends I
of the secondary of said transformer being con
35 nected to a resistance and capacitance in series.
2. The device of claim 1, in which said re
sistance is variable.
3. The device of claim 1, in which an output
22, 23 and leads 24, 25 to a pair of de?ection
plates of an oscillograph cathode-ray tube not
lead is connected between said resistance and
40 capacitance.
The oscillations fed in at I and applied by
4. The device of claim 1, in which said sec
tube 3 pass through the primary 6 of transformer
ondary is grounded.
1, setting up voltages in the coils 8 and ,9 which
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