US2713667A - Audio frequency transformer - Google Patents

Description

2,713,667 AUDI!) FREQUENCY TRANSFGRMER Application Deceniher 21, 953, Serial No. 399,551

1 Claim. (Ci. 336--'l83) This invention relates to an audio frequency transformer primarily adapted for use in plate circuit modula tion of an appropriate radio frequency carrier. The transformer primary is adapted to be energized from push pull amplifying means, while the secondary is adapted to be connected in the plate circuit of a modulating stage for the purpose of modulating a suitable radio frequency carrier. in addition, the invention is applicable to other transformers such as output transformers.

it is well known that capacitance between the windings of an audio transformer and between the windings and ground affects the operation of the transformer. Parasitic series parallel resonant circuits are developed the transformer characteristic is modified as a result. One solution to the problem has been provided in a previous invention by the preser inventor described in Patent No. 2,436,738. In that case, sub-divided windings were used and the windings so connected electrically that capacitive efiects were concentrated and easily compensated for. The sub-divided windings, however, introduced obvious Winding difiiculties. The present invention provides a means or" connecting standard, as opposed to subdivided, windings as an improvement over the previous invention. in addition, the leakage inductance is de creased improving the high frequency characteristic.

The drawing illustrates a transformer wound in accordance with the teachings of this invention. A shell type transformer construction is illustrated, however, the invention is equally applicable to the core type.

The shell type transformer is indicated generally at 10. Laminations ill and 12 are joined and mated in accordance with customary practice. In addition, the windings are assembled on the core in accordance with well known ractice.

The windings, as he 'nbefore stated, are all full length windings and are annularly disposed about the central lamination leg iiindings il -i, 5, ii and Bi are the pri rnary windings. primary windings are wound in the same direction. The direction of windings is indicated by the circle located in the center of each winding. A dot located in the circle indicates winding in one direction and a cross indicates an oppositely wound winding.

The secondary windings are indicated at l5, l7, l8, and 29. Secondary windings l5 and 17 are wound in the same direction as the primary windings. Secondary windings l3 and 20 are wound in the opposite direction.

It is to be understood that the primary and secondary windings are separated by suita le insulation 22.

With respect to the windings, it is preferable that primary windings have the same number of turns although the number of turns may vary in accordance with the characteristic desired.

The windings are provided with terminals hereinafter referred to as inner and outer terminals. The terms inner and outer relate the position of the winding terosates Patent Cffice minal to the central leg 13. The inner terminal is always at the beginning of the winding while the outer terminal is always at the end of that particular Winding.

The primary winding includes the lead wires 23 and 2 and a lead 25 from the center tap which is joined to a source of 15+ potential. The secondary winding includes the lead as from a source of 8+ potential and the output lead 27.

The primary windings are in series relationship. A current path can be traced from the lead 23 to inner ter- .l 28, prii winding 14 to outer terminal 29. From Outer tern a1 2 to inner terminal 38, primary winding 29 and outer terminal 39. Thence to inner terminal 32, primary winding 16 and outer terminal 33. Thence to inner terminal 42, primary winding 21, outer terminal 43 to input lead 24. Thus, the primary windings l4, l9, l6, and 21 are in series respectively.

in the secondary circuit, two parallel circuits are conn tied in series. Each parallel circuit includes two secondary windings oppositely wound. The lead 26 is connected in parallel to inner terminal 33 and outer termirial ll of windings l5 and 2% Findings 15 and 29 are, therefore, in pa allel. Outer terminal 3 inner termini-.1 4i) are ,oined to a common lead which connects inner terminal 3 1: and outer terminal 37' in parallel. Nindings l7 and iii are therefore in parallel. Outer terminal 35 and inner terminal 3d are joined in the common l l 27 which is the output lead. Thus, it can be seen that the oppositely wound windings 15' and 29 are connected in parallel with each other and in series with the parallel connection of windings i7 and 13. As previously indicated, each pair oi windings in parallel in- Cll. vs one winding wound in one direction and one winding wound in the other direction.

As a result of connecting the windings in this manner, distributive capacitive effects are concentrated. The "zisitic resonant effects are concentrated into two paranits so that the effects may be compensated for. itance between primary 21 and secondary 2i), 'een prir iand secondary E5 is concentrated. Similarly, the ance between secondary 2i) and priinary between secondary 15 and primary 16, as well as the capacitance etwcen primary fi and secondary E8, and primary in and secondary 17 is concentrated and as before compensation can be had in any desired manner.

Paving described my invention, i claim:

A transformer consisting of full length primary and secondary w dings annularly disposed the one upon the other in the allowing manner, an innermost first primary, a r 7d secondary, a third primary, a fourth secondary, a nun reversely wound secondary, a sixth primary, a seventh reversely wound secondary, and an eighth prin ,ry, all of said windings having inner and outer termitals respectively and connected as follows; the first, sixth, third and eighth primary windings are connected in series with the outer terminals of an inner winding connected to the inner terminal of an outer winding, the second and seventh secondary windin s connected in parallel to each other and in series with the parallel connection or the fourth. and fifth secondary windings.

References c in the file of this patent UNZTED STATES PATENTS July 19, 1955 w. F. SCHMITT FLIP-FLOP CIRCUIT USING A SINGLE CORE 3 Sheets-Sheet 1 Filed June 4, 1954 w M m a a 004 V- nmd a ,l mm 0 3 2 l 5 2 mm 3 Msrr E m A. \I M c 2 m 3 L) F0. 2 M T. m F W m W m W 2 .H H. a u G L 1 w r .l s w F W 4 m m Q n I w u M 1 m 1 mm. r L s+/ mm.. J a= 4 5 H M ma m 2 B 0H5 mm D MSF m. m 8 U m S St W/LL/AM E SCHM/TT ATTORNEY

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