DE940119C - Filter circuit to dampen unwanted frequencies - Google Patents
Filter circuit to dampen unwanted frequenciesInfo
- Publication number
- DE940119C DE940119C DES29932A DES0029932A DE940119C DE 940119 C DE940119 C DE 940119C DE S29932 A DES29932 A DE S29932A DE S0029932 A DES0029932 A DE S0029932A DE 940119 C DE940119 C DE 940119C
- Authority
- DE
- Germany
- Prior art keywords
- choke
- filter circuit
- capacitance
- capacitor
- unwanted frequencies
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1766—Parallel LC in series path
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1708—Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Filters And Equalizers (AREA)
Description
Übliche Siebglieder zur Dämpfung von unerwünschten Frequenzen, z. B. für die Befreiung der Anodenspannung von störenden überlagerten Wechselspannungen, bestehen, wie in Fig. i gezeigt, aus einer Drossel D im Längszweig und einem Kondensator C im Querzweig. Die Siebwirkung derartiger Siebschaltungen wird durch die Eigen- und Schaltkapazität CL der Drossel stark herabgemindert.Usual filter elements for damping unwanted frequencies, e.g. B. for releasing the anode voltage from interfering superimposed alternating voltages, consist, as shown in Fig. I, of a choke D in the series branch and a capacitor C in the shunt branch. The filtering effect of such filter circuits is greatly reduced by the inherent and switching capacitance CL of the choke.
Der Siebfaktor s ist durch das Verhältnis von Scheinwiderstand der Drossel zu - Scheinwiderstand des Kondensators bestimmt. Unterhalb der Resonanzfrequenz-der Induktivität der Drossel D mit der Kapazität CL steigt der Siebfaktor mit zunehmender Frequenz an. Oberhalb bleibt er annähernd konstant und ist Der Siebfaktor für die Frequenzen oberhalb der Grenzfrequenz kann gemäß der Erfindung dadurch erhöht werden, daß ein eine gegen die Kapazität des Querkondensators der Siebschaltung kleine Kapazität aufweisender Kondensator zwischen einem Abgriff der Drosselwicklung und Erde eingeschaltet wird, beispielsweise zwischen die Wicklungsmitte und Erde, wie dies in Fig. 2 dargestellt ist.The sieve factor s is determined by the ratio of the impedance of the choke to the impedance of the capacitor. Below the resonance frequency — the inductance of the choke D with the capacitance CL — the sieve factor increases with increasing frequency. Above it it remains approximately constant and is The filter factor for the frequencies above the cutoff frequency can be increased according to the invention in that a capacitor with a small capacitance compared to the capacitance of the shunt capacitor of the filter circuit is switched on between a tap of the inductor winding and earth, for example between the winding center and earth, as shown in FIG Fig. 2 is shown.
Die durch Zuschaltung von Cl. erreichte Erhöhung der Siebwirkung kann an Hand des Ersatzschaltbildes der Fig. 3 rechnerisch nachgewiesen werden. In Fig. 3 ist mit L die Induktivität der Drossel D, mit RL der Verlustwiderstand der Drossel und mit CL die zur Drossel parallel liegende Kapazität bezeichnet. Es sind ferner Ue die Eingangsspannung, U" die Ausgangsspannung, n1 und n2 die Windungszahlen der durch den Abgriff gebildeten Teilwicklungen der Drossel D. Für das in Fig. 3 gegebene Ersatzschaltbild ergibt sich für den Siebfaktor Der Minimalwert von yist 4; macht man C, = y - CL, so wird Oberhalb der Grenzfrequenz des in der Drossel verwendeten Blechs gilt annähernd: Ry = coL, und man kann schreiben: d. h. die Wirkung von CL wird durch die Wirkung von Cl aufgehoben, und der Siebfaktor des Siebgliedes steigt auch oberhalb der Resonanzfrequenz von L mit CL, mit zunehmender Frequenz an.The by adding Cl. The increase in the screening effect achieved can be demonstrated arithmetically using the equivalent circuit diagram in FIG. 3. In FIG. 3, L denotes the inductance of the choke D, RL denotes the loss resistance of the choke and CL denotes the capacitance lying parallel to the choke. Furthermore, Ue is the input voltage, U "the output voltage, n1 and n2 the number of turns of the partial windings of the inductor D formed by the tap. The equivalent circuit diagram given in FIG. 3 results for the sieve factor The minimum value of y is 4; if one makes C, = y - CL, then becomes Above the limit frequency of the sheet metal used in the choke, the following applies approximately: Ry = coL, and one can write: ie the effect of CL is canceled out by the effect of Cl, and the sieve factor of the sieve element also increases above the resonance frequency of L with CL, with increasing frequency.
In der Fig. 4 sind die gemessenen Frequenzgänge des Schein"@iderstandes der Drossel (Kurve i), der Siebdämpfung In eines Siebgliedes mit (Kurve 2) und ohne zusätzlichen Querkondensator Cl (Kurve 3) eingezeichnet. Man kann ersehen, daß durch die zusätzliche Kapazität Cl oberhalb der Resonanzfrequenz eine erhebliche Erhöhung der Siebdämpfung erreicht werden kann. Die Siebdämpfung steigt bei den gemessenen Frequenzgängen nicht entsprechend Gleichung (2) an, da die als konzentriert angeordnet behandelte Kapazität CL über die ganze Wicklung der Drossel verteilt ist und die Kopplung zwischen den verschiedenen Wicklungsteilen nicht ideal ist. Das Ersatzschaltbild der Fig. 3 gilt daher nur angenähert. Bei den in Fig. 4 dargestellten Frequenzgängen war die zusätzliche Kapazität Cl = 8o pF an die Mitte der Drosselwicklung angeschlossen. Die Querkapazität C war zu i jcF gewählt. .4 shows the measured frequency responses of the apparent resistance of the choke (curve i), of the screen attenuation In a filter element with (curve 2) and without an additional shunt capacitor C1 (curve 3) is shown. It can be seen that the additional capacitance C1 above the resonance frequency enables a considerable increase in the filter attenuation to be achieved. The filter attenuation does not increase in the measured frequency responses according to equation (2), since the capacitance CL , treated as concentrated, is distributed over the entire winding of the choke and the coupling between the various winding parts is not ideal. The equivalent circuit diagram in FIG. 3 therefore only applies approximately. In the frequency responses shown in FIG. 4, the additional capacitance Cl = 80 pF was connected to the center of the inductor winding. The transverse capacitance C was chosen to be i jcF. .
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES29932A DE940119C (en) | 1952-08-26 | 1952-08-26 | Filter circuit to dampen unwanted frequencies |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES29932A DE940119C (en) | 1952-08-26 | 1952-08-26 | Filter circuit to dampen unwanted frequencies |
Publications (1)
Publication Number | Publication Date |
---|---|
DE940119C true DE940119C (en) | 1956-03-08 |
Family
ID=7479957
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DES29932A Expired DE940119C (en) | 1952-08-26 | 1952-08-26 | Filter circuit to dampen unwanted frequencies |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE940119C (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB519506A (en) * | 1938-11-07 | 1940-03-28 | Gen Electric Co Ltd | Improvements in means for eliminating high frequency oscillations from electric circuits |
CH231984A (en) * | 1942-02-09 | 1944-04-30 | Bosch Gmbh Robert | Electrical system with a source of interference and an end interference choke coil with a ground core. |
-
1952
- 1952-08-26 DE DES29932A patent/DE940119C/en not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB519506A (en) * | 1938-11-07 | 1940-03-28 | Gen Electric Co Ltd | Improvements in means for eliminating high frequency oscillations from electric circuits |
CH231984A (en) * | 1942-02-09 | 1944-04-30 | Bosch Gmbh Robert | Electrical system with a source of interference and an end interference choke coil with a ground core. |
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