DE300143C

DE300143C -

Info

Publication number: DE300143C
Application number: DENDAT300143D
Authority: DE

Description

Die Erfindung betrifft eine Schaltungsanordnung für elektrische Verstärker, und zwar vorzüglich solche, bei denen Entladungsvorgänge zur Erzielung der Verstärkerwirkung ausgenutzt werden, wie sie beispielsweise für Fernsprechzwecke oder für die drahtlose Telegraphic verwendet werden. Sie bezweckt, das Singen oder Pfeifen der Schaltung 'zu vermeiden, das durch die gegenseitige Beeinflussung der Ubcrtrager auftritt, indem Teile des Verstärkten Stromes an die Empfangsstclle der Verstärkeranordnung zurückgelangen. Die Verstärker haben im allgemeinen einen sehr hohen inneren Widerstand. Es müssen deshalb den Ubertragern, durch die der ankommende Strom dem Verstärker übermittelt und der verstärkte Strom weitergeleitet wird, ein hohes Übersetzungsverhältnis und damit sehr hohe Windungszahlen gegeben werden. Demgemäß treten an den Verstärkern und an den Wicklungsenden der Übertrager sehr hohe Wechselspannungen auf. Da ferner die Ubertragcrwicklung sehr hohe Impedanzwerte besitzt, so bedeuten die Kapazitäten ihrer Enden gegen Erde eine verhältnismäßig starke Kopplung zwischen den einzelnen Übertragern. Diese Verhältnisse geben naturgemäß besonders bei Schaltungen mit hohen Verstärkungszahlen Anlaß zu Störungen, da dort schon eine geringe Kopplung Ströme erheblicher Stärke ' von der Sendestelle zur Empfangsstelle der Verstärkeranordnung überträgt.The invention relates to a circuit arrangement for electrical amplifiers, namely especially those in which discharge processes are used to achieve the amplifying effect be used, for example, for telephone purposes or for wireless telegraphic be used. Its purpose is to avoid the circuit's singing or whistling 'that by the mutual influencing of the carriers occurs by parts of the reinforced Current to the receiving stations of the amplifier arrangement get back. The amplifiers generally have a very high internal resistance. It must therefore be the transmitters, through which the incoming current is transmitted to the amplifier and the amplified current is passed on, a high gear ratio and thus a very high number of turns are given. Accordingly, the transformers occur at the amplifiers and at the winding ends very high alternating voltages. Furthermore, since the transfer winding has very high impedance values possesses, then the capacities of their ends to earth mean a proportionate one strong coupling between the individual transformers. These conditions naturally give especially in circuits with high amplification factors cause disturbances, since there already a low coupling of currents of considerable strength 'from the transmitting point to the receiving point of the amplifier arrangement transmits.

In der Erfindung ist ein Mittel angegeben, das die kapazitative Kopplung der Ubertragerwicklungen und dadurch die Störungen in solchen Verstärkeranordnungen beseitigt.In the invention, a means is specified that the capacitive coupling of the transformer windings and thereby eliminates the interference in such amplifier arrangements.

Zur Veranschaulichung der vorliegenden; Verhältnisse ist in Fig. 1 schematisch das Ausführungsbeispiel einer Verstärkerschaltung dargestellt, wobei in Reihe zwei Kathodenröhren T₁, r₂ als Verstärker verwendet werden. Der ankommende Strom gelangt über einen Vorübertrager ν in den ersten Verstärker T₁, dessen verstärkter Strom über einen weiteren mittleren Übertrager m der Empfangsseite des zweiten Verstärkers r₂ zugeführt wird. Ein Nachübertrager η verbindet schließlich die Senderseite des zweiten Verstärkers mit der Vcrbrauchssteile, beispielsweise mit einem Telephon t. Eine Batterie Von 6 Volt liefert den Strom für die Glühelcktroden der Kathodenröhren, eine Batterie von 110 Volt den Anodenstrom für die Senderseiten der Verstärker. To illustrate the present; Relationships is shown schematically in Fig. 1, the embodiment of an amplifier circuit, two cathode tubes T ₁ , r ₂ are used in series as amplifiers. The incoming current reaches the first amplifier T ₁ via a pre-transformer ν , the amplified current of which is fed via a further central transformer m to the receiving side of the second amplifier r ₂ . A post- transmitter η finally connects the transmitter side of the second amplifier with the consumer parts, for example with a telephone t. A battery of 6 volts supplies the current for the incandescent electrodes of the cathode tubes, a battery of 110 volts the anode current for the transmitter sides of the amplifier.

Am ehesten wird das. Pfeifen in einer derartigen Schaltung eintreten, wenn die äußeren Übertrager ν und η miteinander gekoppelt werden. Betrachtet man die Einwirkung der Primärseite p des letzten Übertragers, η auf die Sekundärwicklung s des Vorübertragers v,. so ergibt sieh das in Fig. 2 veranschaulichte vereinfachte Schaltbild, in dem nur die für die vorliegende Untersuchung interessierenden Teile der Schaltung nach Fig. 1 eingetragen sind.Whistling is most likely to occur in such a circuit when the external transformers ν and η are coupled to one another. If one considers the effect of the primary side p of the last transformer, η on the secondary winding s of the pre-transformer v ,. This results in the simplified circuit diagram illustrated in FIG. 2, in which only those parts of the circuit according to FIG. 1 that are of interest for the present investigation are entered.

Die Enden der Primärspule φ des. Nachübertragers η haben gegen Erde E die Teilkapazitäten C₁, C₂, die Enden der Sekundärwicklung s des Vorübertragers ν die Teilkapazitäten C₃, C₄. Die Punkte α und b der Wicklungen s und f sind durch die Batterie infolge deren geringen Widerstandes wie durch einen Kurzschluß verbunden. Hat nun die Erde das Potential O und haben die Enden der Wicklung ψ die Potentiale V₁ und ^ ², so herrscht aoach an dem Punkte α das Poten-The ends of the primary coil φ of the post-transformer η have the partial capacitances C ₁ , C _{2 with} respect to earth E , and the ends of the secondary winding s of the pre-transformer ν have the partial capacitances C ₃ , C ₄ . The points α and b of the windings s and f are connected by the battery as a result of its low resistance as by a short circuit. If the earth has the potential O and the ends of the winding ψ have the potentials V ₁ and ^ ² , then at the point α the potential

Claims

tial V1. Accordingly, a current corresponding to the potential difference V1-0 can flow through the winding s via C3 to earth E. A part of the amplified alternating current to be sent into the telephone t will therefore return to the receiving station of the first amplifier, whereby a new amplification and the associated whistling of the circuit are effected. According to the invention, this phenomenon is eliminated in that individual points of the circuit arrangement, from which already amplified currents can return to the receiving point of the amplifier arrangement, are connected in such a way, preferably by capacitances, that the potential of these points is brought completely or approximately to 0 will.' 3, which corresponds to the circuit diagram of FIG. As a result, the potential difference between the point a, the coil s and the earth E and generally the potential V1 is brought to zero. The approach given above applies to all those winding pairs which, like the one described, are connected by the battery or directly on one side. In this way, all windings are connected to one another except for those to which the receiving and transmitting stations are connected. It may be necessary to render the coupling of these windings harmless. This can be achieved by connecting them on one side to the other windings by means of the connections A1, k "indicated in FIG. 4, i.e. by having one end point λ; or y of the second winding of the transformer is connected to the negative pole of the batteries. Theoretically, it would have the same success if the points α were directly connected to χ and b to y, but in practice this has the disadvantage that due to the grounding of the negative pole of the batteries (for example through connection e) the receiving station carries 110 volts direct current voltage to earth would. Very often, especially if the amplification numbers are not too high, the connections A1, k2 of FIG Part of the amplified current running from b to α not via the winding s and the capacitance C3, but directly via the capacitance C4. ' While the earth connection of the battery shown in FIG. 3 represented a pure short circuit of the current path via s-Cs, the malfunction can under certain circumstances be eliminated if the capacity C4 is considerably increased. Such a circuit is illustrated schematically in FIG. There are further large capacitors connected in parallel to the capacitors C2 and C4. Those of the transmitting and receiving stations with their feed lines to the amplifier arrangement are practically used as these capacities. The connection of these relatively large capacitances - they are indicated schematically by the capacitors C - takes place through the connections klt / e2 of FIG. 4. FIG. 5 shows the protective connections to be made when two tubes are connected in series as described above. Sponsorship τ claims:

1. Circuit arrangement for electrical amplifiers, characterized in that all transfer windings of the amplifier circuit with the exception of the connection windings the receiving and sending point, but also this if necessary Windings, preferably via capacitors, are earthed for the purpose of being carried out by earth capacitances to reduce conditional couplings between the individual transformer windings to a harmless value or ' to be eliminated entirely.

2. Circuit arrangement according to claim 1, characterized in that the transformer windings expediently via an existing connection of one of its ends

(e.g. ά, battery, b in Fig. 3) are grounded together. '

3. Circuit arrangement according to claim 2, characterized in that the existing capacitances of the connection line of the receiving and transmitting point to earth are used as grounding capacitances by one point of the connection lines. ' (e.g. x, y in Fig.

4) to the connection of the Winding ends is connected.

1 sheet of drawings.