US2215790A - Push-pull connected high frequency stage - Google Patents

Description

Sept. 24, 1940. HA HQRNUNG ET AL 2,215,790

PUSH-PULL CONNECTED HIGH FREQUENCY STAGE Filed Dec. l5, 1933 Patented Sept. 24, 1940 PUSH-PULL CONNECTED HIGH FREQUENCY STAGE Heinrich Hornung, Hermann Dirks, and Max Schrumpf, Berlin, Germany, assignors to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof, Germany, a company Application December 13, 1938, Serial No.- 245,390 In Germany November 9, 1938 1 Claim.

The invention relates lto coupling arrangements of the `kind used in push-pull connected high frequency stages and intended especially for use with very short waves, namely, waves in the order of magnitude of some meters or still sho-rter.

It is well known to include a coil in each` of the anode circuits of the two push-pull tubes and to arrange these to act on a coupling circuit common to them. Such two coils are wound in the same direction while rthe coil by which the anode circuits are coupled to an amplifying circuit or a working-,current circuit is disposed in the axis of the anode circuit coils or in an axis parallel to this. Such arrangement has the disadvantage that in the c-ase of a tight coupling and with very high frequencies not only a purely inductive coupling but also a detrimental capacitive coupling is effective while in addition the anode circuit is capacitively de-tuned, this de-tuning being still increased -by the detrimental capacities ybeing asymmetric.

In order to avoid this disadvantage the invention proposes to employ two coils wound in opposition to each other, these constituting the coils arranged to work in push-pull fashion.

In the accompanying drawing an embodiment of the invention is represented by a wiring diagram.

Two electronic tubes I, 2 are arranged to form a push-pull stage of known kind. To these tubes a voltage is supplied from a pre-stage or a control stage over terminals 3 and a -coil 4. Condensers 5 serve in well known manner the purpose of tuning, The direct grid voltage is supplied at G. Other details of the circuit arrangement, such as neutralizing devices and the like, are not disclosed here. Included in. the anode circuits are two component -coils 6, I which in accordance with the invention are wound in opposition to each other. These coils are located in close proximity to one another and in the same axis. The anodev scribed is that the tightest coupling is eective if coil 8 is comparatively far spaced away from coils 6, l, The coupling will `be less tight on either decreasing or increasing this distance. In consequence of this the coupling is almost purely inductive while the capacitive coupling and the capacitive de-tuning of the pre-circuit are small. Also it is of advantage that with the grid coil 4 wound in one direction, as shown, the anode cir-v cuits will not be Iable to react on the grid circuit.

The mode of winding here employed is especially adapted for use in high frequencytransmitters, but is applicable also to receivers.

What is claimed is:

A high frequency 'amplifier comprising two electron tubes having their input circuits connected in push-pull relation, a coil in the output circuit of each tube said two coils being placed in alignment and oppositely wound so as to produce a common i'leld, and a coupling coil positioned in .said eld with its axis normal to that of said two coils.

HEINRICH HORNUNG. HERMANN DIRKS. MAX SCHRUMIPF.

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