US1993880A - Circuit arrangement for neon lamps in telephone systems - Google Patents

Description

March 12, 1935. K. FABER 1,993,880

CIRCUIT ARRANGEMENT FOR NEON LAMPS -IN TELEPHONE SYSTEMS Filed April 8 1932 Karl Faber Patented Mar. 12, 1935 UNITED STATES PATENT OFFICE cmcurr ARRANGEMENT FOR NEON LAMPS IN-TELEPHONE SYSTEMS many ' Application April 8, 1932, Serial No. 604,091

In Germany April 9, 1931 4 Claims.

This invention relates to a circuit arrangement for neon lamps particularly of the type which 'are lighted by an additional voltage for the purpose of causing electromagnetic operations in tele- 5 phone systems. a

In known arrangements of this type, for telephone systems, a direct potential is used as an auxiliary voltage and permanently applied to the neon lamp. For signalling purposes, the neon l0 lamp is lighted by the additional voltage applied to it and consequently a relay placed in series with said lamp is caused to operate. As, however, the striking voltage for the ordinarily used neon lamps is so high that the lamp cannot be lighted 13 by the additional signal potential when only the potential from the existing battery in a telephone exchange is used as an auxiliary potential, an additional batteryhas heretofore been required to attain the striking potential.

This device, according to the invention, eliminates the supplementary exchange battery by generating induced impulses in the secondary winding of a transformer, with-the aid of an interrupt-- er utilizing the battery current or with the aid of the current of an existing alternating current source of supply, said impulses, upon rectification, producing an auxiliary potential for raising the battery potential to the required voltage.

Fig. 1 shows the invention applied to an impulse repeater for a voice frequency dialling system. The line L may be a toll line which terminates in an automatic switch by means of'which it can be selectivelyconnected to other lines. The switch forms no part of the invention and therefore only the motor magnet M is shown. The switch is controlled by voice frequency impulses transmitted over the lineL and repeated to the magnet M of the switch by the relay R of the repeater.

Figs2 shows the invention applied to a neon tube oscillator, which may be used for generating tone currents used for various purposes in telephone systems. As shown in the drawing the os-- the transformer Trl, and relay R. If the primary circuit of the transformer Trl is now inter mittently opened and closed by the interrupter U1, induced impulses of alternate direction are generated in windings II and III of said transformer. The induced impulses of the one direction are transmitted to the neon lamp by the rectifier G1 and impulses of the other direction are likewise transmitted by the rectifier G2 with the result that these potentials are addedto the voltage applied to the lamp from the battery over the above-mentioned circuit. The voltage of the I battery and the ratio of the transformer is such that the total voltage of the lamp approximates the lighting voltage of said lamp. Although in Fig. 1 the battery Btl is shown in two difierent circuits and in Fig. 2 the battery Bt2 is shown at two places, it should be understood that there is only one.battery Btl in Fig. 1, for instance, and only one battery Bt2 in Fig. 2. The batteries are separately shown in order to overcome the necessity of showing separate leads extending from the battery to each of the two circuits, and it is believed that the disclosure is simplified thereby.

When voice frequency alternating current impulses are transmitted over line L, said impulses are transmitted to the transformer Tr2 over the transformer T13 and over an oscillating circuit of a type known for voice frequency signal receivers which is tuned to the signal frequency. The impulses are therefore superimposed on the potential applied to the neon lamp and in this manner cause the lamp to be intermittently lighted. If the frequency of the interruptions and consequently the frequency of the impulses induced in the neon lamp circuit by the interrupter is so calculated that the periods during which the voltage drops below the lighting voltage of the lamp ,are of such a short duration that the lamp will not be extinguished, an uninterrupted flow of current passes through the relay during each received voice frequency impulse. The relay is, therefore, effectively energized once for each impulse, and by the closing of its contact 1' each time, it completes the circuit of the magnet M a number of times, thereby setting theswitch to select the desired line.

The device according to Fig. 2 lows:

In a manner similar to that described in the preceding example the voltage from the battery BT2 is applied to the neon lamp GL2, on'the one hand, over winding I of the transformer 'Ir5 and, on the other hand, over the rectifier -(9:3, winding operates as fol- II of the transformer TM and the variable resistance W1. A condenser K, charged by the battery voltage is, in addition, arranged in parallel with the lamp and the winding I of the transformer Tr5. I

The induced impulses generated by the interrupter, after rectification, increase the constant battery voltage. This results in a charging current passing through the condenser K until the potential applied to the condenser has reached the lighting voltage for the neon lamp. At this moment the condenser is discharged over the neon lamp and winding I of the transformer Tr5. This a discharge causes the potential at the condenser to drop below the lighting voltage for the lamp so that it is extinguished and the cycle is repeated.

The current alterations repeatedly produced in this manner in winding I of the transformer Tr5 set up induced impulses in the secondary circuit of the transformer which, in turn, influence the telephone T, causing the diaphragm of said telephone to oscillate with the result that tones are audible in the telephone.

It is possible to control the charge period of the condenser and consequently also the frequency of the discharges by varying the resistance Wi. In this manner the pitch of the tone produced in.

the telephone may be controlled by the resistance.

Instead of generating the auxiliary potential, required to raise the battery voltage, by means of the interrupter U2, the ringing current source of supply in the exchange maybe used for this purpose, in which case it is connected to winding I of the transformer T14. What is claimed is:

1. In an impulse repeater, two branch circuits having a common portion including a neon tube connected in series with a relay, a battery, and the secondary of a transformer, a filter circuit connected to the primary of said transformer, 'a rectifier connected in each branch of said neon tube circuit, asecond transformer with its secondary connected to said filter circuit, an incoming line with the primary of said second transformer connected across it, a third transformer 'with its secondary connected'in said branch circuits, an interrupter connected in series with a battery and the primary of said third transformer, means controlled by said interrupter and, said third transformer for raising the circuit voltage to approximately the flash voltage of said neon tube, means for transmitting voice frequency impulses over said incoming line, said impulses causing said neon tube to strike allowing said relay to operate, and means controlled by said relay for repeating said impulses.

2. In an impulse repeater, two branch circuits flash voltage of said neon tube, means contained in said circuit for allowing current to pass only in one direction through said neon tube, an incoming line, means for inductively connecting said neon tube circuit across said incoming line, means for transmitting voice frequency impulses over said incoming line, said impulses causing said neon tube to strike and operate said relay, and means controlled by said relay for repeating said impulses.

3. In an impulse repeater, two branch circuits with a common portion including a neon tube in series with a relay and a battery, the voltage of said battery being below striking voltage of said neon tube, a transformer with its-secondary connected to the branch circuits, means for impressing a pulsating current on the primary of said transformer causing an induced voltage in said branch circuits, means in said branches for allowing current to flow in only one direction through said neon tube, said induced voltage when added to said battery voltage raising the latter sumciently to .approach the striking voltage of said neon tube, an incoming line, means for inductively connecting said neon tube circuit across said incoming line, means for transmitting voice frequency impulses over said incoming line, said impulses causing said neon tube to strike and operate said relay, and means, controlled by said relay for repeating said impulses.

4. In an impulse repeater, two branch circuits with a common portion including a neon tube connected in series with a relay and a battery, a rectifier connected in each branch of said circult, a transformer with its secondary connected to said branch circuits, means including an interrupter connected inseries with a battery and the

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