US2106286A - Gas-filled tube circuits - Google Patents

Description

Ja 25, 1938. L, K, WART 4 2,106,286

GAS-FILLED TUBE CIRCUITS Original Filed Nov. 5, 1935 INVENTOR LESll/tl/ Y ATTORNEY Patented Jan. 25, 1938 UNIT STATES 2,106,286 GAS-FILLED TUBE CIRCUITS Leland Kasson Swart, signer to American Company,

Mountain Lakes, N. 1..- Telephone and Telegraph a corporation of New York Application November 5, 1935, Serial No. 48,379 Renewed November 30, 1937 11 Claims.

This invention relates to electrical circuits and systems. More particularly, this invention relates to recording systems and is intended to be especially useful for recording electrical voltages. The apparatus and circuits of this invention are applicable to record steep wave front voltages and will record direct voltages as well as alternating voltages of steep wave front.

This invention also relates to gas-filled tubes and to circuits for gas-filled tubes. More particularly, this invention relates to arrangements for measuring voltages or currents and obtaining measurements from low voltages applied to the measuring apparatus through cold cathode gas-filled tubes.

Cold cathode gas-filled tubes generally require fairly high potentials to ionize the gas between their electrodes. Such high potentials may be obtained through the use of input transformers or through biasing sources of potential or both. The use of input transformers in measuring circuits is undesirable especially for measuring or recording steep wave front impulses and transients, due to the change in the wave form the transformer will produce for frequencies outside of its normal operating range, this change arising from the non-linear characteristics of the transformer. If on the other hand biasing potentials are employed to reduce the initial operating voltage, which exceed the sustaining voltage between the input electrodes of the tube, special means must be employed to restore the gas to its deionized condition after withdrawal of the applied voltage. In accordance with this invention, the biasing potentials exceed the sustaining voltage of the tube and the output circuit includes special circuits to restore the gas to its original deionized state. Moreover, even though the output circuit may include arrangements for deionizing the gas,,yet where the applied voltage at the input exceeds the sustaining voltage, the invention further provides means for temporarily reducing :the voltage in the input circuit of the tube below the sustaining value. To accomplish this latter feature, a resistance or resistance and condenser may be inserted into the input circuit of the tube to produce a potential drop across its terminals upon the passage of current therethrough for counteracting the effect of the biasing potential.

The invention will be better understood from the detailed description hereinafter followin when read in connection with the accompanying drawing which shows two embodiments of the invention merely for the purpose of illustration.

In Figure 1, an impedance Z1 is bridged across the input circuit. The outer adjustable terminals are connected to the cathodes K1 and K2 of gasfilled tubes N1 and N2 which may be of the hot or cold cathode type, the interconnecting circuit -5 including resistors Z2 and Z: which are employed to limit the current applied to these cathodes. The source of potential B1 is connected between a point approximately midway between the terminals of impedance Z1 and the cathodes K3 and K4 of the two tubes through a resistor Z4. The latter source of potential is greater than the sustaining voltage of the tubes but less than the voltages required to start gaseous ionization within these tubes. Source B1 is employed to bias the cathodes K1 and K2 with respect to the corresponding electrodes K: and K4 and it reduces the voltage supplied by the input circuit through impedance Z1 required to initiate gaseous ionization within the tubes.

The anodes A1 and A: of tubes N1 and N2 respectively are connected together and are part of a so-called work circuit which includes the windings of relays R1 and R2, the battery or other source B2 and the impedance Z4. The terminal common to the windings of relays R1 and R2 is connected to the cathodes K3 and K4 through a resistor Z5 and a condenser C1.

The relay R1 is a vibrating relay and it operates to suppress the voltage in the work circuit and hence to deionize the gas within both tubes. This is described in more detail in my Patent 1,977,256 issued October 16, 1934. The relay R2 acts as a work relay and it operates recording mechanism'relay R3, as will be subsequently described. The relay R: has its winding in a circuit which includes the armature and contact of relay R2 and the source 32. The current in the winding of relay R1 is controlled by the resistor Z6. The relay is nevertheless under the control of relay R2. 40

The relay R3 is of a slow-acting type, its armature closing its associated contact slowly. As the armature and contact of relay R3 are in the resetting circuit of the tubes N1 and N2, the delay so introduced is for the purpose of providing ample time for the recording mechanism, of which relay Ra is a part, to operate properly. The resetting circuit just referred to includes the armature and contact of relay R3, the armature and contact of relay R1 and the parallel circuit which includes the winding of the latter relay as one branch and the resistor Z5 and condenser C1 as the other branch.

The arrangement of Fig. 1 operates as follows: The potential impressed across impedance Z1 is divided into two parts which are applied through resistors Z2 and Z: to the cathodes K1 and K3 and K1 and K; respectively of the tubes N1 and N2. The potential impressed upon one of these pairs of cathodes will be aided by the potential of source B1 and the other potential will be opposed by that of B1. If it be assumed that the potential applied to impedance Z1 is an alternating potential and of a sufllcient magnitude, then the gas within both tubes will become alternately ionized by the incoming potential. Upon the ionization of tube N1, current will flow through the work circuit which includes, among other things, the windings of relays R1 and R2 and the anode A1 and the cathode Ka of tube N1. Both of the relays R1 and R2 will operate and the operation of relay R2 will cause relay R3 to operate. The armature and contact of relay R3 complete a circuit as follows: The armature and contact of relay R3, the contact and armature of relay R1, the winding of relay R1, the anode A1 and the cathode & of the tube N1 back to the armature of the relay R3. This circuit will withdraw potential from the winding of relay R1 and hence reduce the potential between the anode A1 and cathode K1 to a value less than that required to sustain the glow between these electrodes of the tube. At the same time the current through the winding of relay R2 is increased because all of the potential B: is applied thereto. The latter current also flows through resistor Z1 and is in a direction'to oppose that produced by source B1 and applied to the cathodes K1 and Ka of tube N1. As the increased biasing potential exceeds the sustaining voltage at the input electrodes of the tube, this counter voltage of course materially reduced the potential between the cathodes K1 and K3 below the sustaining voltage and, in the absence of additional voltage at the input circuit, 5.. e. applied from the input circuit across the upper half of impedance Z1, the glow between electrodes K1 and K3 will be extinguished. Upon deionization of the gas within tube N1, potential becomes removed from the winding of relay R1, the armature of the latter relay will leave its contact and the potentials of sources B1 and B2 will be restored to the anode A1 and cathode K: and K1 of tube N1. If, however, potential is still applied across within tube will reoperate.

Thus, relay R1 vibrates continuously while voltage is applied from the input circuit and holds relay R2 continuously operated which in turn holds relay R3 continuously operated. However, when the armature of relay R1, leaves its contact and on disappearance of the voltage applied by the input circuit, the tube N1 becomes deionized and remains deionized and relays R2 and R3 restore to normal.

The same sequence of events occurs when the potential applied by the input circuit is reversed in polarity except that the electrodes of tube N: are brought into the operating circuits.

The resistor Z5 and absorb the voltage set up by the winding of relay R2 when the armature of relay R1 leaves its contact. Absorption of this voltage is required in order to prevent reionization of the gas within either tube on account of the addition of the voltage drop produced across the winding of relay R: to that of source B2.

In Fig. 2 the relay R1 includes an additional armature at the left. This armature is connected to the center top of impedance Z1. The contact condenser C1 function to.

of this additional armature is connected to the negative terminal of source B1. A resistor Z1 is inserted between the positive terminal of source B1 and the center top of impedance Z1.

Upon the operation of relay R1, the closure of the right hand contact of the relay will complete a circuit, such as already described with respect to Fig. 1, to deionize the gas between the electrodes A1 and & of tube N1 or between the electrodes A2 and K4 of tube N2, these electrodes being in the work circuit. Upon the closure of the left hand contact of relay R1, the potential applied between the two cathodes of each tube will, in the absence of additional voltage across impedance Z1, be reduced practically to zero and the gas be tween these cathodes will become deionized. The resistor Za and condenser C: may be connected across the left hand armature and contact of relay R1, as shown, in order to prolong the time in which the voltage across both pairs of cathodes is maintained below the sustaining voltage to insure complete gaseous deionization between these cathodes.

Although this invention has been shown and described in certain particular arrangements merely for the purpose of illustration, it will be understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the appended claims.

What is claimed is:

1. The combination of a gas discharge tube having input and output circuits connected to its electrodes, the electrodes of the tube forming a plurality of discharge paths one of which extends to the input circuit and another to the output circuit, means including sources 01' voltage connected respectively in the input and output circuits for ionizing the gas between all of the discharge paths or the tube, and means responsive to the discharge of the gas in the output circuit for simultaneously de-ionizing the gas within all of the discharge paths formed by the electrodes to which both circuits are connected, said means being connected to the output circuit.

2. The combination of a gas-filled tube having three electrodes, an input circuit connected to two of the tubes electrodes through which voltage may be applied to ionize the gas within the tube, an output circuit including a source of voltage connected between the third electrode and one of the other electrodes of the tube, and means responsive to ionization of the gas within the tube for feeding voltage in the output circuit back to the input circuit to reduce the effective voltage of the input circuit below the value required to sustain gaseous ionization within the tube.

3. The combination of a gas-filled tube having three normally cold electrodes, an input circuit connected to two of the electrodes, an output circuit connected to the third electrode and one of the other electrodes, two sources of potential one of which is connected to the input circuit and the other to the output circuit, and means connected to the output circuit for periodically deionizing the gas between all of the electrodes of said tube.

4. The combination of a gas-filled discharge tube having at least three electrodes to which input and output circuits are connected, individual' sources of potential in said input and output circuits, and means responsive to the energization of the output circuit for continuously and periodically reducing the effective voltage of both of said sources of potential.

5. The combination of a three-electrode gasfilled tube, a source of potential, an impedance connected in series with said source between two of the tubes electrodes, a second source of potential, a work circuit including said impedance and said second source oi potential and connected between the third electrode and one of the other electrodes, means for continuously transmitting pulsating current through said work circuit, and means for periodically deionizing the gas between all of the electrodes of the tube, said means being connected to said work circuit.

6. The combination of a gas-filled tube havin electrodes, at source of potential for biasing one of the electrodes with respect to another electrode to a potential exceeding the sustainin voltage between said electrodes, a second source of potential, a load circuit connected to the third electrode and one of the other electrodes and including said second source of potential, said load circuit including means for periodically deionizing the gas between the electrodes to,

which said load circuit is connected and for simultaneously neutralizing the voltage oi said source.

7. The combination a three-electrode gasillled tube, voltage biasing means connected between two of the electrodes and of a value exceeding the sustaining voltage therebetween, a source of potential, a work circuit connected between the third electrode and one of the other electrodes and including said source of potential, and means for periodically deionizing the gas between the two electrodes'to which the work circuit is connected, said means including means connected to said work circuit for periodically deionizing the gas between the first two electrodes.

8. Voltage recording apparatus comprising a three-electrode gas-tilled tube, an impedance to which incoming voltages are applied, a source of potential connected to said impedance and to two of the tubes electrodes, a vibrating relay, a load device, a recording relay, a second source of potential supplying current through the winding of the vibrating relay and the third electrode and one of the other electrodes of the tube to said load device, means responsive to flow of current to said load device to operate the recording relay, and means connected to the armature and contact of said vibrating relay to periodically nullity 'the effect. of both sources of potential.

9. The combination of a three-electrode gasfllled discharge tube, a source of potential exceeding the sustaining voltage value but below the breakdown voltage value connected to two of the tubes electrodes, a similar source con-.

nected to the third electrode and one of the other electrodes, means responsive to the ionizationoi the gas within .the tube to periodically reduce the eflective potential of both sources below the sustaining voltage value, said means being connected to the aforementioned circuit extending to said third electrode and said other electrode.

. 10. The combination of a three-electrode gasfllled tube, input and output circuits each connected to two 01' the tubes electrodes one of which is common to both circuits, two sources of potential connected respectively to said input and output circuits the magnitudes of which exceed the sustaining voltage value between the electrodes to which each circuit is connected, and means responsive to the application of additional voltage to the input circuit to simultaneously, synchronously and periodically deionize the gas between the two pairs of electrodes, said means including means for feeding voltage from the output circuit to the input circuit to reduce the elective voltage of the input circuit.

11. In a circuit having a three-electrode gasiilled tube providing two discharge gaps, two sources of potential one for each gap, the magnitude oi each of said sources exceeding the voltage required to sustain glow in its corresponding gaps, and means for periodically extinguishing the glow oi each gap, said means including means tor returning potential across one gap to the circuit oi the other gap to reduce the eiiective potential across the latter gap.

LELAND KABSON SWART.

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