US1950399A - Relaxation circuit oscillator - Google Patents

Description

March 13, 1934. w -n5 1,950,399

RELAXATION CIRCUIT OSQILLATOR v Filed Feb. 11, 1930 l l INVENTOR.

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A TORNE) Patented Mar. 13, 1534- ore rice

2 Claims.

(Granted under the act of March 3, 1883, as amended April 39, 1928; 37% (l. G. 757) My invention relates broadly to relaxation circult oscillators and more particularly to a circuit arrangement for transferring energy delivered by a relaxation circuit oscillator to a work circuit.

One of the objects of my invention is to provide a circuit arrangement for a relaxation oscil lator having means for transferring relatively high output voltage to a work circuit with a high IQ degree of stability.

Another object of my invention is to provide a circuit arrangement for a relaxation oscillator in which harmonic frequencies may be intensified :and a higher voltage output obtained from a in position in the circuit adjacent the anode of the oscillator.

Still another object of my invention is to provide an arrangement of relaxation circuit for the regeneration of audio frequency oscillations which the anode lead includes an impedance element across which the audio frequency energy is delivered for transmission to a work circuit from the anode circuit of the relaxation oscillator.

Other and further objects of my invention reside in the circuit arrangement for a relaxation circuit oscillator as described more fully in the specification hereinafter following by reference to the accompanying drawing, in which:

Figure 1 diagrammatically illustrates one form of circuit for the relaxation circuit oscillator 02 my invention; Fig. 2 shows a modified circuit arrangement for the relaxation oscillator of my 111- vention; Fig. 3 shows a still further modification of the relaxation oscillator of my invention; Fig. 4 is a further modified showing of the relaxation oscillator of my invention; Fig. 5 illustrates the circuit arrangement of my invention as applied to a three-grid type of electron tube in a relaxation oscillator system; and Fig. 6 shows a modification of the circuit of Fig. 4.

The thermionic vacuum tube, when connected in a circuit with the proper combination of electrical impedances and electrcrnotive forces, will give rise to alternating current energy. There are many known circuits in which such a tube will produce electrical oscillations, the most common of which is the inductance capacity oscillator with a sinusoidal output. Not so well known, but destined to become of importance in 50 several new fields is another type of oscillator,

the oscillations of which consist of aperiodic pulses of E. M. F. occurring in cyclic order, and whose output, therefore, is far removed from sine wave form. Such an oscillation occurs when the electric or magnetic held or" a capacity or an inductance is built up until a set or limiting conditions is reached, the field then being dissipated until a second set of limiting conditions causes a second reversal and the field is built up again. The action of the field in building up to a potential applied through an impedance or dissipating itself through an impedance may be referred to as relaxation, and since the period of the oscillation in question is determined by the time of relaxations, the circuit producing such action is called a relaxation oscillator. In one form of relaxation oscillator an electron tube with two grids is used with resistance and capacity only; such as oscillator is described in the Van der Pol Patent No. 1,744,935, issued January 28, 1930. The frequency of the relaxation oscillator dep nds on the values of the circuit elements employed. While the output of the relaxation oscillator may be of considerable amplitude, it is possible to control the output frequency by a higher frequency of very small amplitude. This characteristic oi the relaxation oscillator makes it available for a number of important applicatime.

I have discovered that the operation of a relaxation oscillator may be stabilized by introducing resistance into the anode lead across which the high frequency energy may be taken off at relatively higher voltage than has been obtainable heretofore in relaxation oscillators where the voltage is taken all at other points in the relaxation oscillator. I have found that the output voltage may be further increased by connecting an inductance in circuit with the anode of the relaxation circuit oscillator and the inductance coupled or connected to an output circuit. A transformer may be connected in the anode lead of the relaxation circuit oscillator to obtain the required voltage in the output system. For purposes of stabilizing the relaxation circuit, resistance elements may be interposed in series or parallel relation with respect to the inductance in the anode lead of the relaxation circuit oscillator. My invention is applicable to multiple grid electron tubes and the circuit arrangement which I have illustrated is particularly adapted for frequency division operation.

Referring to the drawing in more detail, reference character 1 designates an electron tube which includes cathode 2, anode 5, and grid electrodes 3 and e. Grid electrode 3 functions as the inner or control grid, while grid electrode 4 operates as a shield grid. High potential source 6 winch has been illustrated for the purpose of explaining the principles of my invention as 9.

battery, has its positive terminal connected to anode 5 through resistance 7, resistance 7 having terminals 711 and 7b forming the output terminals of the circuit. Control or inner grid 3 is connected through resistance 9 with the point of positive potential 8 in the battery system 6. The cathode is heated from any suitable source such as represented by battery source 12. Condenser 11 is connected in shunt between inner grid 3 and shield grid 4. Resistance 10 connects between shield grid 4 and negative terminal of battery system 6.

In Fig. 2, I have shown an inductance element 14 connected in place of the resistance element 7 illustrated in Figure 1 Where the inductance element 14 has terminal leads 14a and 14b at opposite ends thereof leading to the output system. The inductance 14 yields a relatively high voltage and intensifies the harmonics.

In Fig. 3, I have shown the circuit arrangement of Fig. 2 including inductance element 14 which connects to the output system through leads 14a and 1411 where the inductance 14 connects in series with resistance element 15. This combined arrangement of inductance and resistance in the output lead increases the stability of operation of the relaxation oscillator over that stability which is obtainable with the circuit of Figure 2.

Fig. 4 illustrates a relaxation oscillator system in which the anode circuit lead includes the primary winding 17 of transformer 16 where transformer 16 has secondary winding 18 connecting to the output system. This arrangement yields a relatively high output voltage and is stabilized in operation by means of series connected resistance 19 and by parallel connected resistance 20 in circuit with primary winding 17. Good results are also obtained with the circuit of Fig. 4 using series resistance 19 alone and omitting shunt resistance 20.

In Fig. 5 I have shown the circuit of my invention employed in a three-grid relaxation oscillator system wherein an electron tube 21 is provided having cathode 22 and anode 25 with grid electrodes 23, 24, and 26 disposed therebetween. The high potential source is illustrated at 30 and there are connections to each of the grid electrodes and to the anode through resistance elements from the source of high potential 30. That is to say, grid 26 connects through resistance 29 with the negative terminal of battery 30. Grid 24 connects through resistance 28 with the negative terminal of battery 30. Grid electrode 23 connects through resistance 31 to a point of positive potential in battery 30*. Anode 25 connects through resistance 32 with the positive terminal of battery 30. Leads 32a and 32b ex"- tend from opposite ends of resistance 32 and form the output terminals for the relaxation oscillator. Condenser 27 connects between grid electrodes 23 and 24 of the relaxation oscillator.

Fig. 6 shows a modification of the circuit of Fig. 4 wherein resistance 20 is in shunt with the primary winding 17 and no resistance is employed in series with the primary winding and the anode.

While I have described my invention in certain of its preferred embodiments, it will be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

The invention herein described may be manufactured and used by or for the Government of the United States of America. for governmental purposes without the payment of any royalties thereon.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a relaxation circuit oscillator, an electron tube having cathode, anode, and a multiplicity of grid electrodes, a capacity element connected between two of said grid electrodes, impedance elements connected in circuit between said cathode and each of said grid electrodes, a transformer comprising primary and secondary windings, said primary winding being connected in circuit with said anode, a resistance element disposed between said primary winding and said anode, a resistance connected in shunt with said primary winding, and terminal connections extending from said secondary winding for utilizing oscillations generated by said relaxation circuit oscillator.

2. In a relaxation circuit oscillator, an elec-.- tron tube including a cathode, an anode, and a multiplicity of grid electrodes, a capacity element connected between two of said grid electrodes, impedance elements connected in circuit with each of said grid electrodes, said impedance elements having substantially negligible inductive effects, an output circuit, a source of potential, a transformer comprising primary and secondary windings, a resistance, said primary winding, said source of potential, and said resistance being connected in series in said output circuit, a second resistance connected in parallel with said primary winding, and terminal connections extending from said secondary winding for utilizing oscillations generated by said relaxation circuit oscillator.

WESTLEY F. CURTIS.

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