US2006969A

US2006969A - Amplifying device

Info

Publication number: US2006969A
Application number: US702160A
Authority: US
Inventors: Steimel Karl; Klotz Ernst
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1932-07-24
Filing date: 1933-12-13
Publication date: 1935-07-02
Anticipated expiration: 1952-07-02
Also published as: NL38500C; DK50601C; AT143039B; DE640517C; CH166024A; AT141275B; FR758305A; DK48823C; DE666191C; CH166025A; NL41232C; DK49718C

Description

y 1935- K. STEIMEL ET AL I 2,006,969

AMPLIFYING DEVICE Filed Dec. 15, 1953 INVENTOR KARL 672-74161 A-RMST KLOTZ ATTORNEY Patented July 2, 1935 UNITED STATES AMPLIFYING DEVICE Karl Steimel and Ernst Klotz, Berlin, Germany, assignors to Telefunken Gesellschaft fiir Drahtlose Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application December13, 1933, Serial No. 702,160

In Germany December 28, 1932 Claims.

An object of the present invention is to provide a vacuum tube amplifier having at least four grids and utilizing such an amplifier tube to amplify both radio and audio frequency os- 5 cillations.

A further object-of the invention is to control one of the grids of such an amplifier by means of the modulation voltage developed in the plate circuit of a diode detector which is coupled to one of the grid circuits of the radio frequency amplifier portion of the tube.

Other objects of the invention will become apparent to those skilled in the art as the description thereof proceeds. For a better understanding of the invention, however, reference is made to the accompanying drawing in which the single figure'is a schematic circuit diagram of an arrangement embodying our invention.

In our application, Serial .Number 673,850 filed June 1, 1933, of which the present application is a continuation in part, we disclose a vacuum tube amplifier having four grids in which the radio frequency signal energy is impressed on the grid near the cathode, the second grid serves as a screen grid, while the circuit of the third grid includes an oscillation circuit from which radio frequency voltage issupplied to the fourth grid or one nearest the plate. This arrangement provides on the one hand a feed-back connection and on the other hand, by suitable choice of the coupling means and bias potential of the fourth grid between it and the plate, plate rectification takes place so that the modulation component is secured in the plate circuit.

In the present arrangement we prefer to impress the radio frequency voltage obtained in the circuit of the third grid on a distinct and independent rectifier, such as a diode or plate rectifier or the like and to impress the audio frequency voltage separated therefrom, after complete or partial elimination of radio frequency currents, upon the fourth grid and ensure audio frequency amplification between this grid and the plate. The special advantage of this arrangement is that the voltage impressed on the fourth grid may be determined or regulated at will. On the contrary, a certain limitation exists in the circuits disclosed in the above mentioned application, in that the voltage at the fourth grid is utilized for rectification as well as for regeneration.

As shown in the drawing the antenna may be connected to the first grid circuit by primary 5 and secondary coil 6 the latter being tuned to the desired incoming signal frequency by variable condenser 1. The screen grid 2 is connected to a positive source of potential, while grid 3, which serves as the plate of the radio frequency amplifier portion of the tube, "is connected to any desired positive source'of potential such as a battery 23 through primary 15 of a radio frequency transformer whose secondary l6 may be tuned to the signal frequency by a variable condenser E1. The ends of coil [6 are connected to the plate l9 and cathode 20 of a diode vacuum tube detector l8, a high resistance l3 shunted by a by-pass condenser 2| being connected in circuit as shown. The modulation v0ltage of the incoming signal as developed across resistance [3 is impressed through condenser l0,

which has a low impedance to audio frequency currents, on the grid nearest the plate or anode P. A high resistance It provides a grid leak for grid 4 and it may be given the desired bias by means of a battery l2. The cathodes of the amplifier tube and detector tube may be connected together by a lead 22, as shown. The

amplified audio frequency current of the plate circuit may be supplied to the output terminals 9 through the audio transformer 14 whose primary 8 is in the plate circuit.

Having described our invention what we claim and desire to secure by Letters Patent is:

1. In an amplifying device, the combination of a vacuum tube having a cathode, a signal control grid, a second grid, a plate and an auxiliary grid located between said plate and second grid, a circuit tuned to the signal frequency connected between said signal control grid and cathode, a load circuit connected between said second grid and cathode, a detector coupled to said load circuit, means for impressing the detected current on said auxiliary grid and an output circuit connected to said plate.

2. In an amplifying device, the combination of a vacuum tube having a cathode, a signal control grid, a third grid, a screen grid located between said signal grid and said third grid, an anode, an auxiliary grid, means for applying a positive potential to said screen grid, acircuit tunable to the signal frequency connected between said signal grid and cathode, means for impressing modulated .radio frequency signal currents on said tunable circuit, a load circuit connected between said third grid and cathode, a detector coupled to said load circuit and connections between said detector and said auxiliary grid arranged to impress the detected currents thereon, and an output circuit connected to said anode.

3. In an amplifying device, the combination of a vacuum tube having a cathode, a signal control grid, a third grid, a screen grid positioned between said named grids, an anode, an auxiliary grid positioned between said third grid and anode, means for maintaining said screen grid at a constant positive potential, a circuit tunable to the signal frequency connected between said signal grid and cathode, means for impressing modulated radio frequency currents on said tunable circuit, a load circuit including the primary of a radio frequency transformer connected between said third grid and cathode, means for tuning the secondary of said transformer to the signal frequency, a diode detector having its plate connected to one end of said secondary coil, a high resistance connected between the other end of said secondary coil and the cathode of said diode detector, a circuit connecting the last named end of said secondary coil to said auxiliary grid, and a circuit connected to the plate of said tube arranged to transfer the amplified audio frequency currents to a pair of output terminals.

former primary coil, means for tuning the secondary of said transformer to the signal frequency, a diode detector having its plate connected to one end of said secondary coil, a resistor connected between the other end of said secondary coil and the cathode of said detector, a condenser having one side connected to the last named end of said secondary coil and its second side to said auxiliary grid and an output circuit connected to the plate of said tube.

5. The combination defined in the preceding claim in which the series connection of a source of bias voltage and resistor is connected between the second side of said condenser and the cathode of said detector.

KARL STEIMEL. ERNST KLOTZ.