' April 11, 1950 J, M, |__ JANssEN 2,503,739 CIRCUIT ARRANGEMENT PRODUCING A PHASE-DISPLACEMENT HAVING A SUBSTANTIALLY CONSTANT VALUE ' Filed Jan. 51, 1947 1.30 - 1.80 1.00 - A I” +10° 00 110 ° 0.5 1.5 ——>- (0113C 3% AGENT. Patented Apr. 11, 1950 , 2,503,139 UNITEDFLSTATES PATENT orrice PHASE DISPLACEMENT HAVING A SUB STANTIALLY CONSTANT VALUE ‘Johannes Marinus Lodevicus J anssen, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn, trustee ' Application January 31, 1947, Serial No. 725,460 ' In the Netherlands February 18, 1946 3' Claims. (01. ‘178-44) , 2 1, It is often desirable, inter'alia if use is made of a so-called reactance tube, to deduce an auxiliary voltage from an available alternating voltage, the former exhibiting a certain phase angle e. g. 90° In the .vector diagram shown in Fig. 2' the vectors Va and Vc indicating the voltages across R and‘C of Fig. 1 respectively, extend normally to one another, so that their point of intersection,‘ with respect to the last-mentioned voltage. In the drawings: upon a frequency variation, moves over the‘cir cumference of a circle of which V2‘ (voltage across ~ Fig. 1 shows a circuit arrangement used in ‘ex the secondary transformer winding) is the diameter. Consequently, the value of vector Vu is always l/gvi, but the phase angle 9) between Va plaining my invention. Fig. 2 is a vector diagram related to Fig. 1. Fig. 3 is a circuit diagram used in explaining my invention. ' H) ' of my invention. ' Fig. 5 shows curves illustrating the operation of Fig. 4. ' A circuit arrangement commonly used for this panying drawing. of the two output terminals. The series-con nection of a resistance R and condenser C is con _ which it is represented as a source of voltage purpose is represented in Figure 1 of the accom is branched at the centre A and connected to one variable. Vu’ having an internal impedance Zi consisting of the parallel-connection of R and _C. If wRC=1, Vu’ is normal to Vi. In this case the phase angle of the internal impedance Zi amounts to —45°. ’ The available voltage Vi is supplied to the primary of transformer T, of which the secondary and V1 The circuit arrangement shown in Figure 1» may be replaced by that shown in Figure 3, in "Fig. 4 shows the wiring diagram of one form Upon connecting an external impedance Zu be;-v 20 tween points A and B in Fig. 3, which equally has a phase angle of —45°, the resulting output volt age appearing between A and B amounts to nected in parallel with this secondary winding. Zu As an alternative the condenser C may be re placed by an inductance. The junction pointv vB i.’ e. areal fraction of Vu’ so that it is also normal to <Vi.. If in this circuit wRC=1 all phase angles except?‘ two terminals has a value corresponding to half that of Va, which will remain 90°, change if only the voltage across the secondary, consequently a ?xed ratio relatively to V2‘, and furthermore ex- 30 the phase angles of Vu' and hibits a phase-displacement covering an angle Z“, which. depends upon the relative value of R and m C and furthermore upon the frequency. If between R and C is connected to the other output ' terminal. The output voltage Vu between these wRC=1(w=21rf) the phase angleamounts to 90°. change by opposite amounts. Upon calculation However, this angle di?ers from 90° in regard to 35 it is found that this can be ensured to a close all frequencies other than J‘. The invention provides a circuit arrangement approximation by inserting between A and B the series-connection of a resistance R1 and a con which permits an auxiliary voltage to be deduced denser C1, the impedance of which series-con from an alternating voltage, the auxiliary voltage nection is small with respect to Zi, and at the relatively to the last-mentioned voltage having 40 same time the relation should hold: not only a constant ratio in value, but also ex- _ _ hibiting a phase-displacement substantially inwRc_wR1c1_a dependent of the frequency. If wRC1=b then To this end, according to the invention, in a R (71 b circuit-arrangement of the aforesaid kind an 45 RI=E=E auxiliary resistance R in series with an auxiliary condenser C1 (as the case may be an auxiliary inFigure 4 represents the wiring diagram of one ductance L) is connected in parallel with the form of construction of the invention. This dia output terminals, these circuit elements having gram corresponds to that shown in Fig. 1 and such values that R1C1=RQ and R1 is at hast 50 comprises in addition the series connection of a several times smaller than R. resistance R1 and a condenser Cl between points This will be explained more fully with refAandB. erence to the diagrams shown in Figs. 2, 3 and 5, Figure 5 represents several curves indicating Figure 4 representing a wiring diagram accordthe variation of the output voltage and of the ing to the invention. 55 phase displacement respectively as a function of : the frequency and more particularly for several having values at which the output voltage estab-l values of the ratio b/a. lished at said output terminals has a predeter From these curves it mined phase displacement substantially inde appears’ that even if pendent of frequency within the frequency range of the input voltage. B: 5 a . , 2. Apparatus for deriving a phase-displaced the phase displacement, upon a frequency varia tion of 50% will not change more than 10°, which will often be su?icient. The variation of the out ' output voltage from an alternating input voltage whose frequency is variable within a predeter mined range, said apparatus comprising a trans put voltage as a function of the frequency is sub- ‘ former having a primary and a centertapped sec stantially independent of the ratio b/a. An in ondary, a resistance R, a condenser C connected crease of this ratio i. e. the-insertion of a smaller in series with resistance R. across said second impedance Zu between A and B, and consequently ary, “output terminals connected between the centertap of said secondary and the junction of series connected resistance R and condenser C, varesistance R1, and'a condenser 01 connected in series with resistance R1 across said output ter minals. said resistances and condensers having a decrease of the available output voltage is use- ' ful only when it is of importance to make the phase displacement highly independent of the frequency. ‘ Also for values of the phase displacement other _ than 90° the invention permits a satisfactory fre values satisfying the expression: quency-independency over a large __frequency range to be obtained by making the ratio ZuIZi_ sufficiently small. ' 1, \/RCR1C1 2”“ > " For any desired phase angle q: ‘the equation where fa is the average frequency of said range and the R:R1 exceeds unity by an amount at which the phase displacement of the output voltage established across the output terminals is substantially independent of frequency within the frequency range of the input voltage. so that the phase angle q? will be most inde pendent of the frequency if , 3. Apparatus for deriving a phase-displaced 30 output voltage from an alternating input voltage whose frequency is variable within a predeter mined range, said apparatus comprising a trans former having a primary and a centertapped sec °’ #1301210, ondary, a resistance R, an inductance L connect 'Consequently,_when it is desired tov obtain a 09 ;vi ed in series with resistance R across said'sec 1 phase displacement practically independent of the‘ ondary, output terminals connected between the frequency over a more or less Wide frequency range it is necessary to satisfy the aforesaid equa; tion, in which w=21r times the average frequency over this range. What I claim is: 1. Apparatus for deriving a phase-displaced output voltage from an alternating input voltage whose frequency ' is variable Within a prede ' termined range, said apparatus comprising a transformer having a primary and a center tapped secondary, a ?rst resistance, a ?rst-re-: actance connected in series with said ?rst resist ance across said secondary, output terminals" 44 centertap of said secondary and the junction of the series connected resistance R, and inductance L, said resistances and inductances having values satisfying the expression: . l 521 > 211' f a _ LL‘ where fa. is the average frequency of said range» and the ratio R :R1 exceeds unity by an an amount at which the phase displacement of the, output‘ voltage established across the output terminals is substantially independent of frequency within , connected between the centertap of said second-‘ 50 the frequency range of the input voltage.~ ary and the junction of said series connected J OHANNES MARINUS ?rst resistance and ?rst reactance, a second re LODEVICUS JANSSEN. sistance, and a second reactance connected in series with said second resistance across said out put terminals, said resistances and reactances No references cited.