BRIONVEGA CRISTALLO 123 23 " YEAR 1960

The BRIONVEGA CRISTALLO 123  23 "  is a B/W television from BRIONVEGA designed by R.Bonetto with 23 inches (59cm) B/W Screen with VHF selector and UHF selectors tuner.

- The  BRIONVEGA CRISTALLO 123  23 " is first television developed and produced by BRIONVEGA   the emerging italian industry era with special design in the 59's / 60's.

- The  BRIONVEGA CRISTALLO 123  23 " is also first BRIONVEGA television  honoured with a premium at the  " triennale of Milan In Italy in 1960 " .International Art Meeting.The Milan Triennial XII was the Triennial in Milan sanctioned by the Bureau of International Expositions (BIE) on the 5 May 1959.

The Milan Triennial (Triennale di Milano) was established in 1923 as a 3 yearly architecture and industrial design exhibition held in Monza and then, since 1933, in Milan.

- The  BRIONVEGA CRISTALLO 123  23 " is also first BRIONVEGA television with both VHF selector and UHF selector channel tuning features.

Tuning is obtained with rotatable drum selectors for VHF and variable rotatable capacitor for UHF.

A rotatable drum containing twelve pre-defined channel-specific filters determines the received channel, where the inductors of the input matching, the channel filter and the LO tank circuit are changed. The tuner is divided into two chambers for maximum isolation between the sensitive RF input and the mixer-oscillator-IF section with its much larger signals. Also on the drum there are eventually two separate sub-modules.

It's completely based on tubes technology.

With this concept, which essentially turned the tuner module into a kind of Lego building block construction, many different tuners became possible. Depending upon the country of destination and its associated standard and IF settings, the required filter modules would be selected. Service workshops and tv fabricants could later even add or exchange modules when new channels were introduced, since every inductor module had its individual factory code and could be ordered separately. As a consequence more versions of the tuner were produced, covering at least standards B, B-for-Italy, C. E, F and M.

The principle of the drum tuner. On an axis two times 12 regularly spaced channel-specific filter modules are mounted. In front are twelve channel filter modules for both the channel filter and LO tank circuit tuning. Seven contacts are available, and one module is shown removed. The second row contains 12 modules with five contacts for the input filter circuit. In the tuner module the front section (for mixer-ocillator and channel filter) is separated by a metal shield from the rear RF input and pre-amp section. [Philips Service "Documentatie voor de kanalenkiezers met spoelenwals", 1954]

Examples of the filter modules as used in the drum tuner. Left the 5-contact input filter, right the 7-contact BPF and LO tank filters. In both modules the coils are co-axial for (maximum) mutual coupling.

The second new valve introduced in the tuners family was the PCF80, a triode-pentode combo valve specifically designed for the VHF mixer-oscillator role. First order the circuit principles didn't change too much from the previous ECC81 based generation, with the triode acting as a Colpitts oscillator with a tuned feedback from anode to grid. The oscillator voltage was minimally 5V at the grid, and would be inductively coupled to the input of the mixer pentode. This inductive coupling was achieved by putting the oscillator coil S7 and the BPF coils S5 and S6 on the same rod inside the drum tuner filter modules, see Fig.5 above. By adjusting the distance between these coils for each channel filter module, the coupling constant could be kept more or less constant across all channels, providing as much as possible a frequency-independent mixer performance. For the mixer the pentode replaced the previous triode, providing more feedback isolation between anode and grid. All in all the new tuner must have given a considerable performance improvement compared to the previous generation.

Television receivers currently being manufactured for consumer use were capable of operation in either the VHF (very high frequency) or UHF (ultra high frequency) bands of frequencies. In order to provide this capability, however, it is necessary to include two separate tuners or tuning circuits in the television receiver with one of these circuits being utilized for VHF reception and the other being used for UHF reception. The VHF tuner conventionally is a turret type of tuner having 13 detented positions which accomplish the coarse tuning or channel selection of the VHF tuner and a separate control is provided to effect the fine tuning at each of the channel positions. Generally, mechanical channel selecting devices for VHF television tuners fall into two groups, namely, the rotary-switching type or the turret types. Turret type tuners include an incrementally rotatable channel selector shaft for selectively connecting certain ones of a plurality of tuned circuit elements to each of a plurality of channel selector positions. UHF tuners generally employ a separate control mechanism or a tuning knob and use a dial indicator of a type commonly found in manual radio receivers. UHF tuners for television receivers are usually of a continuous tuning type similar to the tuning system adapted for radio sets. Therefore, the tuning in UHF channels has been extremely difficult as compared to the tuning in VHF channels. Such continuous tuning systems for the UHF tuners has heretofore been sufficient, since only two or three UHF channels have been authorized in one locality. However, where more UHF channels, namely seven or eight channels, are available for reception, a non-continuous type UHF tuner, which enables simpler tuning operation, is desired. Nevertheless, this continuous tuning system has heretofore been satisfactory, because there were only 2 or 3 UHF band channels or stations available for reception in an area. But, where there are an increased number (7 or 8 or more, for instance) of UHF band channels or stations available for reception, a non-continuous or intermittent tuning system as is adopted for the VHF tuner is preferable.

More desirably, the fine tuning control is presettable, so that the desired channel may be readily selected by merely turning the main channel switch-over shaft. The use of two separate tuning control mechanisms in order to effect the VHF and UHF tuning of the receiver is  at best; and when a receiver is provided with remote control capabilities, generally only the VHF band of frequencies may be remote controlled and the UHF channels still must be selected manually at the receiving set location.Conventional turret tuners still leave room for improvement, especially as far as minimizing the tuner size and dimension, and simplifying the assembly, as well as lowering the manufacture costs and improving the tuner performance are concerned.

Brionvega is (was) an Italian electronics company, established in Milan in 1945.

Vega, BP Radio, Brionvega, Brion & Pajetta; Milano, Lissone (MI) (I)
Abbreviation: vega
Products: Model types
Summary: Society B.P.M. (1945) Vega - BP Radio (Fabbrica Apparecchi e Accessori Radio, Perito Ind. Brion & Ing. Pajetta)
Via Pacini 59, Milano (1948)
Via Ampère 61, Milano (ca. 1950)
Brionvega Formenti Sèleco Spa
Via Dante Alighieri 43, 20035 Lissone / MI

Good design is no longer simply for an "elite" but is demanded by a far wider audience interested in continuous development.With so many designs and products available, how is it possible to distinguish a truly outstanding design from one that is simply trendy. World famous designers: Hannes Wettstein, Mario Bellini, Richard Sapper, Marco Zanuso, Castiglioni brothers and Ettore Sottsass, have tried to come up with the answer to what constitutes the perfect design. In finding inspiration, when designing for Brionvega, these people look beyond every day fashion and look for examples which are outstanding in their beauty. They also pay attention to people's attitude and how they relate to everyday objects.


Historically speaking, Brionvega is one of the most famous radio and Television manufacturers, thanks to its products, born from the collaboration with well-known design firms. Over the years, from its establishment, Brionvega has made some industrial design corner-stones, such as the radio "cube" TS502 from 1963, the Algol and Doney portable TV, and the radio-phonograph RR126.

 The company was founded in 1945 by Giuseppe Brion and engineer Pajetta. Initially called B.P.M. Company and manufacturing electronic components, the business became known as Brionvega in 1960. In the early 1960s, two unusually designed portable television sets, designed by Marco Zanuso and Richard Sapper, were launched by Brionvega by the names "Doney" (1962) and "Algol" (1964).

Brionvega became famous for a number of exceptional designs (algol, doney, ts502, rr126). A few of their designs found their way into the Museum of Modern Art (MoMA), New York.

2007 DONEY CVT set ( V.Cometti) numbered edition, ALGOL CVT set (V.Cometti) numbered edition,
ALPHA LCD CVT set (V.Cometti)

2002 TVC DOGE 32" (M.Bellini)
1992 GLASS CUBE CVT set (M.Bellini) crystal cubic-shaped television
1992 25" and 28" QUADRO CTV set (M.Bellini) forerunners of the flat screens
1990 15" BEST CTV set (M.Bellini) with triangular rear case
1989 11" ALGOL CTV set (M.Zanuso) newly designed
1988 SINTESI CTV set (R.Lucci-P.Orlandini) with the characteristic orientable loudspeakers
1983 26" CORO PANSOUND CTV set (R.Lucci-P.Orlandini)
1980 23" MEMPHIS CTV set (E.Sottsass) limited series
1980 20" LED CTV set (M.Bellini)
1979 26" ALTA FEDELTA' CTV set (M.Bellini) high audio performance technology
1978 15" MONITOR TV Set (M.Bellini) whose packaging will serve as model for the manufacturing of future PC monitors
1978 15" MONITOR TV Set (M.Bellini) whose packaging will serve as model for the manufacturing of future PC monitors
1969 17" VOLANS TV Set (M.Bellini)
1969 BLACK ST 201 TV Set (M.Zanuso-R.Sapper) first small size TV set designed to be a decorative piece
1968 ASTER TV Set (M.Bellini) sculptural, audio devices in the base
1967 12" DONEY TV Set (M.Zanuso-R.Sapper) evolution of the 14" version
1964 19" SIRIUS TV Set (M.Zanuso)
1964 11" ALGOL TV Set (M.Zanuso-R.Sapper) on display at the MoMA in New York.
1962 14" DONEY TV Set (M.Zanuso-R.Sapper)first transistor portable TV set in Europe, awarded with the Compasso d'Oro.
1961 23" ORION TV Set (M.Albini-F.Helg)
1959 23" CRISTALLO TV Set (R.Bonetto)
1954 Television is becoming widespread.
1945 Giuseppe Brion and engineer Pajetta found the B.P.M. company (initially electronic components), which in the 1960's will become Brionvega, specialized in TV sets.

The BRIONVEGA stylish design is well recognized around the world for it's particularity.
The television here in collection The BRIONVEGA CRISTALLO 23 " 123   . is a clear example of that style.

Rodolfo Bonetto

(Milan 1929-1991) designer. Began his activity in 1958 operating in the durable consumer goods sector and industrial goods sector in various fields: from domestic appliances to bathroom fittings, automobiles, musical instruments, radios and airplane instrumentation panels. “A cultured factory worker”, as V. Gregotti described him, he successfully managed to combine a thorough understanding of production technologies and materials with ergonomic considerations and a very ethical attitude to formal research. He taught at the Hochschule für Gestaltung of Ulm (1961-1965), and has been awarded six Compasso d’Oro for objects such as the Sfericlock alarm clock (Veglia Borletti, 1963); the O.C.N. numerical control machine tool (Olivetti, 1967); the automatic microfilm apparatus (BCM, 1970); the interior for the 131 Supermiriafiori (Fiat, 1978). Between 1972 and 1975 with N. Matsunaga, he designed the tooling centre Horizon 2 (Olivetti) up to the Wiz multi-purpose generator. Creator of the Fire engine (1984) for Fiat, the Rotor, public telephone for Sip (1989) and the mechanism for automatic gate opening Cross 6 (Novotecnica), he has been a member of national and international juries and president of Ic sid from 1981 to 1983. Bonetto is the only Italian designer never to have put his name to architectural projects, as he was always solely interested in large-scale production. After his death, he was dedicated the Compasso d’Oro 1991 as a tribute to his overall activity, which now continues with the Bonetto Design Studio, run by his son Marco, who, in 1994, founded the Bonetto Design Centre in Montecarlo dedicated to his father’s memory, a centre for ideas and services for the new areas of design.
[from A. Pansera ( edited by), Italian Design Dictionary, Cantini, Milan 1995, in the updated volume (January 1998, edited by Tiziana Occleppo) from the CD Rom “Navigando nel design” (edited by A . Pansera, art direction Oderso Rubini for Studio Equatore) 1995]

Rodolfo Bonetto had his first meeting with Raimondo Guzzini in 1967, as is shown by an entry in the records in which Bonetto used to carefully note down all his working relationships. He designed for the Fratelli Guzzini until 1971 and up to 1986 for iGuzzini illuminazione.

Some References:

^ "Ex Sèleco a un imprenditore udinese", Articolo del Messaggero Veneto del 18 febbraio 2010

"Brionvega History". Brionvega.tv. Retrieved 18 February 2012.
  "2008 Brionvega reissues". brionvega.tv.
 
"Cuboglass TV History". brionvega.it.

 

A good point  on good  old  B/W Televisions.....................

The Sixties was a time of great change for TV. At the start of the decade there were just monochrome sets with valves, designed for 405 -line transmissions at VHF. By the end there was 625 -line colour at UHF, with transistorised chassis that used the odd IC.

The following decade was one of growth. The "space race" had begun in 1957, when the USSR launched Sputnik 1 and terrified the Americans. Thereafter the USA began to spend countless billions of dollars on space missions. This got underway in earnest in the Sixties, with the announcement that America would be going all out to get a man on the moon by the end of the decade. There followed the Mercury series of earth - orbit missions, then the Apollo launches. Success was achieved in 1969. Most of these missions were televised, and in those days anything to do with space was hot stuff. It was inevitable that everyone wanted to have a television set. At the time an average receiver would be a monochrome one with a 14in. tube - there was no colour until 1967. It would cost about 75 guineas. 
TV sets were often priced in guineas (21 shillings) as it made the price look a bit easier on the pocket. Anyway 75 guineas, equivalent to about £78.75 in 2000's currency, was a lot of money then.  For those who couldn't, rental was a good option. The Sixties was a period of tremendous growth for rental TV. 
Much else was rented at that time, even radios, also washing machines, spin driers, refrigerators and, later on, audio tape recorders (no VCRs then). 
For most people these things were too expensive for cash purchase. 
There were no credit cards then. And when it came to a TV set, the question of reli- ability had to be taken into account: renting took care of repair costs. 

TV reliability.........The TV sets of the period were notoriously unreliable. They still used valves, which meant that a large amount of heat was generated. The dropper resistor contributed to this: it was used mainly as a series device to reduce the mains voltage to the level required to power the valve heaters. These were generally connected in series, so the heater volt- ages of all the valves were added together and the total was subtracted from the mains voltage. The difference was the voltage across the heater section of the dropper resistor, whose value was determined by simple application of Ohm's Law. 
As valves are voltage -operated devices, there was no need to stabilise the current. So the power supply circuits in TV sets were very simple. They often consisted of nothing more than a dropper resistor, a half or biphase rectifier and a couple of smoothing capacitors. If a TV set had a transformer and a full wave rectifier in addition to the other components, it was sophisticated!
 As the valve heaters were connected in series they were like Christmas -tree lights: should one fail they all went out and the TV set ceased to function. Another common problem with valves is the cathode -to -heater short. When this fault occurs in a valve, some of the heaters in the chain would go out and some would stay on. Those that stayed on would glow like search- lights, often becoming damaged as a result. Dropper failure could cause loss of HT (dead set with the heaters glowing), or no heater supply with HT present. When the HT rectifier valve went low emission, there was low EHT, a small picture and poor performance all round. CRTs would go soft or low emission, the result being a faint picture, or cathode -to -heater short-circuit, the result this time being uncontrollable brightness. On average a TV set would have twelve to fourteen valves, any one of which could go low -emission or fail in some other way. All valves have a finite life, so each one would probably have to be replaced at one time or another. The amount of heat generated in an average TV set would dry out the capacitors, which then failed. So you can see why people rented! 

The CRT could cause various problems. Because of its cost, it was the gen- eral practice to place its heater at the earthy end of the chain. In this position it was less likely to be overloaded by a heater chain fault. But during the winter months, when the mains voltage dropped a bit, it would be starved of power. This would eventually lead to 'cathode poi- soning' with loss of emission. The 'cure' for this was to fit a booster transformer designed to overrun the heater by 10, 20 or 30 per cent. It would work fine for a while, until the CRT completely expired. At about this time CRT reactivators came into being - and a weird and wonderful collection of devices they turned out to be. Regunned tubes also started to appear. You couldn't do this with the `hard -glass' triode tubes made by Emitron. These were fitted in a number of older sets. Yes, they were still around, at least during the early Sixties.

Developments................... A great deal of development occurred during the Sixties. Many TV sets and radios made in the early Sixties were still hard -wired: the introduction of the printed circuit board changed the construction of electronic equipment forever. The first one was in a Pam transistor radio. PCBs were ideal for use in transistor radios, because of the small size of the components used and the fact that such radios ran almost cold. 
They were not so good for use with valve circuitry, as the heat from the valves caused all sorts of problems. Print cracks could develop if a board became warped. If it became carbonised there could be serious leakage and tracking problems. In addition it was more difficult to remove components from a PCB. Many technicians at that time didn't like PCBs. As the Sixties progressed, transistors took over more and more in TV sets. They first appeared in a rather random fashion, for example in the sync separator stages in some Pye models. Then the IF strip became transistorised. Early transistors were based on the use of germanium, which was far from ideal. 

The change to silicon produced devices that were more robust and had a better signal-to-noise ratio. 
Car radios became fully transistorised, and 'solid-state' circuitry ceased to be based on earlier valve arrangements. Many hi-fi amplifiers had been transistorised from the late Fifties, and all tape recorders were now solid-state. 
Both reel-to-reel and compact -cassette recorders were available at this time. Initially, audio cassette recorders had a maximum upper frequency response of only about 9kHz. 
To increase it meant either a smaller head gap or a faster speed. Philips, which developed the compact audio cassette and holds the patents for the design (which we still use in 2000!) wouldn't allow an increase in speed. Good reel-to-reel recorders had a fre- quency response that extended to 20kHz when the tape speed was 15in./sec. 
This is true hi-fi. In time the frequency response of compact -cassette recorders did improve, because of the use of better head materials with a smaller gap. 
This led to the demise of the reel-to-reel audio recorder as a domestic product We began to benefit from spin-offs of the space race between the USA and the USSR. 
The need to squeeze as much technology as possible into the early computers in the Mercury space capsules used by the USA lead to the first inte- grated circuits. 
This technology soon found its way into consumer equipment. Often these devices were hybrid encap- sulations rather than true chips, but they did improve reliability and saved space. The few chips around in those days were analogue devices.  To start with most UHF tuners used valves such as the PC86 and PC88. They were all manually tuned. Some had slow-motion drives and others had push -buttons. They didn't have a lot of gain, so it was important to have an adequate aerial and use low -loss cable..............................

BRIONVEGA CRISTALLO 123 23 " CHASSIS (VEGA) INTERNAL VIEW

  

 

 

The chassis of the  BRIONVEGA CRISTALLO 123  is entirely based on Tubes technology and completely hand made and one of the first with PCB boards ( GRP17, GRP10, GRP12) for some sections:

 Tubes used: EC86 EC86 PCC88 PCF80 EF183 EF184 PCL84 PCF80 PCF80 PL36 EF80 PCL82 ECC82 PL84 PY81 DY86  CRT:AW59-90

Constant potential transformer / Constant Voltage transformer :

 The old B/W Tubes Television set was powered with a External Voltage stabiliser / Constant Voltage transformer unit (portable metal box) because  There was intermittent significant rapid line voltage dips here and there that were rather annoying when watching a tube set with an unregulated power supply (like all tvs of ancient times) and it eliminates the line dip issue completely.

(The, of mine, Pictured Constant Voltage transformer unit taken as example is a "KURTIS" STV/3 Italian Manufactured in Milan (Italy) in Year 1954 with a 250 VA power displacement and developed under Italian Patent 50499. It's clearly reported that input may be universal within -20%  +10% variations, output is precisely regulated within 1% range.........................click on pictures to enlarge them at full screen......)

The invention relates to voltage regulators of the type employed to supply alternating current and a constant voltage to a load circuit from a source in which the line voltage varies. They are particularly advantageous in connection with commercial applications such as amplifiers for talking motion pictures, amplifiers for radio transmitters,  Television sets (tubes),   mercury arc lamps, X-ray apparatus, etc.







 
Features : Instantaneous Voltage regulation. No effect of input Transient and spikes on the output. Sinusoidal output waveform. Was a  perfect answer and remedy for all types of electronic equipment. The  CVT have been designed to give you total protection against power related problems and to condition the power to suit the needs of Tubes television sets based equipment. It effectively regulates voltage variation, suppresses transients and bridges short interruptions/dips.

Basics: Ferro Resonant type Constant Voltage Transformers - CVT, the AC mains power the input winding, which The input winding normally runs at very moderate Flux linkage levels. The output winding exhibits an intrinsic energy characteristic and this energy storage operate in conjunction with mains capacitor to produce self-generated AC flux Field which is indirectly extracted from the Input Winding.
These Constant Voltage transformer or CVT use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output with a varying input. The ferroresonant approach is attractive due to its lack of active components, relying on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage.

The ferroresonant action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency it can maintain an almost constant average output voltage even as the input voltage varies widely.

All problems related to variation / fluctuation in Voltages are effectively handled because of this principle and a constant voltage output of ± 1% is given.

 INVENTOR: JOSEPH G. SOLA.

The  invention relates to an improved constant potential transformer by means of which variations of input voltage over a wide range of limits may take place without affecting the output voltage to any substantial extent.

One of the objects of my invention is to provide a constant potential transformer which is compact as a unit and which may be economically manufactured.

o1 It is another object of my invention to provide a transformer of this type in which the efficiency and input power factor are high while the temperature rise of the magnetic core is low.

A further object of my invention is to provide 1., a transformer, the outputvoltage wave of which will have very little distortion and the device will be satisfactory for various commercial applications.

The invention consists of the novel constructions, arrangments and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of certain preferred embodiments illustrated in the accompanying drawings, wherein,Fig. 1 is a sectional view of one form of construction that may be used; Fig. 2 is a diagrammatic illustration of the wiring arrangement that may be used in connection with a construction such as that shown in Fig. 1; Fig. 3 is a sectional view of another form of construction embodying the principles of my invention; Fig. 4 is a diagrammatic illustration of the wiring arrangement that may be used in connection with a construction such as that shown in Fig. 3; Fig. 5 is a diagram showing the vector relations between the various voltages obtained in the illustrated constructions at different values of input voltage; and Fig. 6 is a graph showing the relation between the magnitudes of various voltages obtained in the illustrated constructions as the input voltage is varied.

Like characters of reference designate like parts in the several views.

Referring to Figs. 1 and 2, it will be seen that a core type of transformer construction is illustrated, the closed magnetic circuit 10 of which comprises a stack of I-shaped laminations II in abutting relation with the end legs 12a of a stack of E-shaped laminations 12, which may be held 5 together by any suitable means. On the end portion A of the core bar 11, I have provided a primary winding 13, the terminals 14 and 15 of which are adapted to be connected with a source of alternating current, the voltage of which from time to time may fluctuate or vary substantially. g On the end portion B of the core bar 11, I have mounted a winding 16, which is in spaced relation to but magnetically coupled with the winding 13, the winding 16 having terminal leads 17 and 18 and an intermediate tap 19. That part of the winding 16 between the lead I7 and tap 19 may be considered as an output or load winding, and the entire winding 16 between the leads 17 and 18 may be termed an intermediate winding.

The magnetic core 10 is provided with a high leakage reactance path between the windings 13 and 16 which in the form shown comprises the central leg 12b of the E-shaped laminations and which terminates short of the core bar 1 thereby providing a non-magnetic or air gap 20 between said leg 12b and the core bar II. In this arrangement, a condenser 21 is connected by leads 22 across the terminals 17 and 18 of the winding 16.
The lead 17 forms one side and the tap 19 the other side of what may be termed an output or load circuit. In the arrangement shown, an auxiliary winding 23 is positioned over the winding 13 and is magnetically coupled therewith, the terminals 24 of said winding 23 being connected in series in the lead 19 of said output circuit. In Figs. 3 and 4, I have illustrated my invention in connection with a well-known shell type of transformer having two closed magnetic circuits 10 and 10a comprising a straight central core bar 25 of I-shaped laminations, the sides of which are in abutting contact with the end legs 26a of the E-shaped laminations 26 and the end legs 27a of the E-shaped laminations 27, said parts being held in operative relation by any suitable means. On the end portion A, of the core bar 25, I have mounted a primary winding 28 the terminals 29 and 30 of which are adapted to be connected to a source of alternating current, the voltage of which may fluctuate substantially from time to time. Another winding 31 is positioned on the end portion B of the core bar 25, the winding 31 being in spaced relation to but magnetically coupled loosely with the winding 28.

A condenser 32 is connected across the terminals 33 and 34 of the winding 31. Another winding 80 35 is mounted on the end portion B of the core bar 25, in the arrangement shown the winding 35 being positioned over and magnetically coupled tightly with the winding 31. The terminal 36 of the winding 35 leads to one side of what may i be termed an output circuit. An auxiliary winding 37 is positioned on the end portion A of the core bar 25 and in the arrangement illustrated the winding 3I is positioned over and magnetically coupled tightly with the winding 28.

A lead 38 connects the winding.37 in series with the winding 35, the lead 39 of the winding 37 forming the other side of the aforesaid output circuit. The winding 35 may be termed an output or load winding and the winding 31 may be considered as an intermediate winding. The closed magnetic circuits described are each provided with a high leakage reactance path between the windings 28 and 37 on the end portion A of the core bar 25 and the windings 31 and 35 on the end portion B of said core bar, which in the arrangement shown comprise the central legs 40 and 41 of the respective E laminations 26 and 27. The shunts 40 and 41 terminate short of the adjacent sides of the core bar 25 thereby providing non-magnetic or air gaps 42 and 43 between the legs 40 and 41 and the core bar 25.

In Figs. 2, 4, 5 and 6 Vo represents the voltage across the output circuit, Vp shows the input voltage on the primary winding, Vs indicates the voltage derived from the winding 16 between the lead 17 and tap IS, and from the winding 35 forming parts of the respective output circuits, and Vpa is the component of the output voltage taken across the terminals of the auxiliary winding 23 or 31, as the case may be.
In Fig. 5, I have shown the vector relations of the various voltages in either arrangement at a certain power output and at different values of primary voltage. The various voltages are either not primed or are primed to correspond to the different values of Vp which is varied. As shown, Vpa is nearly 180* out of phase with Vs, and hence the vectorial sum Vo of the two is approximately their numerical difference.

In Fig. 6, I have illustrated graphically the relation in the constructions described between Vs, Vo, Vpa and Vp ata certain power output.

The principles upon which my improved transformer constructions operate will be clear from a detailed consideration of the construction shown in Figs. 3 and 4. The flux set up by applying a potential across the primary winding 28 will link with winding 31 and cause a definite reactance to be set up by that winding. As the voltage on the. primary winding is increased from zero to a higher level, the flux threading through winding 31 tends to increase in nearly direct proportion to the primary flux, due to the re5 luctance caused by the air gaps 42 and 43, a very slight amount leaking through the shunts 40 and 41. As the Induced E. M. F. reaches a higher value in winding 31 a critical point is reached where resonance takes place, since the reactance of the effective inductance of the winding 31 and the capacity reactance of the condenser 32 are approximately equal at the frequency of the voltage impressed on the winding 28. that is to say.

WCfL where f is the frequency of the voltage impressed on the primary winding 28, L is the effective 70 Inductance of the winding 31, and C is the capacity of the condenser 32. Under this resonant condition, a definite amount of current will flow in the resonant circuit, comprising the winding 31, condenser 32 and leads 33 and 34, and such t6 current will be limited by the constants of that circuit, with the result that a potential will be set up across the winding 31 and a corresponding amount of magnetic flux will be set up in the end portion B of the core bar 25.

It is well known that the inherent characteristic of a resonant circuit is such that its power vector may be many times greater than that of the generator which supplies the energy to the resonant circuit; in this case the energy is supplied by the primary of the transformer to the resonant circuit comprising winding 31 and condenser 32. By varying the primary voltage across winding 28 so that the magnetic density of section A thereof will still remain under the maximum magnetic density of section B of the core, with which the resonant circuit is associated, the change of flux density in section A of the core due to line variation in the primary will have no appreciable effect on the resonant circuit as the reluctance of the leakage path will be under that of section B of the core and flux will leak through the leakage path between the primary and resonant core portions, which leakage path comprises the shunts 40 and 41 and their respective nonmagnetic gap portions 42 and 43. It is due to this leakage reactance path also that the co-efficient of coupling between the primary winding 28 and the aforesaid resonant circuit is reduced to a certain optimum value, thereby maintaining a balanced condition so that the resonant circuit will continue to oscillate with the maximum current therein at a frequency equal to the frequency impressed on the primary winding. Under this state of resonance, winding 31 will set up a magnetic field in the core portion B which will remain practically constant so long as the density in the magnetic field of the core portion A remains at a lower density than that of the core portion B. It follows that this substantially constant field strength in core portion B will produce also a substantially constant voltage across the terminals of winding 31 and condenser 32, and this voltage will remain at practically a constant level regardless of variation of voltage applied to the primary winding 28. The aforesaid resonant circuit, therefore, becomes a constant primary source of voltage for any winding such as the winding 35 that is directly coupled to the winding 31. This coupling can be effected in any desired way, for example, by means of an auto-type transformer arrangement as shown in Fig. 2, or by mounting the winding 35 over the winding 31 as shown in Fig.

4. In the Fig. 4 construction, the output voltage of the windings 35 will also have a practically 5, constant level voltage independent of the voltage variation in the primary winding 28 so long as the circuit which includes the winding 31 remains in resonance.

The auxiliary regulating winding 37 is coupled go to the portion A of the core and is used to change the percentage of regulation of Vo across the terminals 36 and 39 of the output circuit with a variation of Vp. Since this auxiliary winding 37 on core portion A is directly coupled to the pri- 05 mary winding 28, the voltage induced will always be proportional to the turns ratio of primary winding 28 and the auxiliary winding 37.

A very constant level of voltage Vo across the terminals 36 and 39 may be obtained by suitably T0 apportioning the number of turns of said auxiliary winding 37 in relation to the number of turns in the winding 35. Any percentage of regulation of output voltage in relation to variations of Vp also may be obtained from terminals Ts 2 t ist. .y 36 and 39,-for example, an increase in the prinrary voltage on winding 28 will produce a decrease in output voltage Vo by properly arranging or apportioning winding 37 in relation to the winding 35.

The relation of voltages described has been upon the assumption that the transformer is on an open output circuit, that is to say, with no load on the terminals 36 and 39. If a load be applied on said terminals, a magnetic flux in the aforesaid resonant circuit will be developed corresponding to the load on said output circuit thereby unbalancing the magnetic flux in section B of the core. This density change in core section B will in turn affect the stable relation of the flux in core sections A and B and also the leakage reactance through the aforesaid shunt paths thereby causing a greater amount of useful flux from core section A to thread through core section B, which compensates for the energy used by the consuming circuit and at the same time maintains the resonant circuit in the desired oscillating condition.

It will be readily understood that in transformers embodying the principles of my invention the primary winding electrically connected to the source serves to induce voltage to the resonant circuit which is separated from the primary circuit by a high leakage reactance path, thereby providing a low co-efficient of coupling between the primary and the resonant circuits. The aforesaid resonant circuit may be considered as the primary or main source of controlling energy to the winding 35 and hence'to o3 the output or consuming circuit of the transformer.

My improved constant potential transformers are compact and efficient, and are of a small size relative to their power output as compared with other and more cumbersome and expensive apparatus intended for the same purpose. My improved transformers operate at an inherent high power factor, and the output voltage is very close to a pure sine wave.

My improved transformers may be used for many different purposes. They are particularly advantageous in connection with commercial applications such as amplifiers for talking motion pictures, amplifiers for radio transmitters,  Television sets (tubes),   mercury arc lamps, X-ray apparatus, etc.

I wish it to be understood that my invention is not to be limited to the specific constructions shown and described, except so far as the claims may be so limited, as it will be apparent to those skilled in the art that changes in the constructions and arrangements may be made without departing from the principles of my invention.

I claim:1. In a constant potential transformer, the combination of a magnetic core, a winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding.
2. In a constant potential transformer, the 7T combination of a magnetic core, a winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core in spaced relation to said first winding, said core having magnetically disposed between said windings a magnetically 6 permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding.

3. In a constant potential transformer, the combination of a closed magnetic circuit comprising first and second core portions, a winding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said second core portion, said circuit providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

4. In a constant potential transformer, the 85 combination of a closed magnetic circuit comprising first and second core portions, a winding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said second core portion in spaced relation to said first winding, said circuit having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

5. A constant potential transformer comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core adapted to be connected to an output circuit, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the load winding substantially constant regard- 05 less of fluctuations in the input voltage comprising a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding.

6. A constant potential transformer comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core in spaced relation to said primary winding and adapted to be connected to an input circuit, said core having magnetically disposed between said winlings a magnetically permeable shunt with a non-magnetic gap portion.; and means for maintaining the potential across the load winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding.

7. A constant potential transformer comprising in combination a closed magnetic circuit comprising first and second core portions, a primary winding on said first core portion adapted to be Sconnected to a source of alternating current of fluctuating voltage, a load winding on said second core portion and adapted to be connected to an output circuit, said magnetic circuit having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the load winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including a conSdenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed upon the primary winding, the third winding being on the second core portion and in inductive relation to the load winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

8. A constant potential transformer comprising in combination a magnetic core, a primary wind40 ing on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core adapted to be connected to an output circuit, said core providing a high leakage reactance path for a portion of the 45 flux to thread through one of the windings to the exclusion of the other winding, a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the 50 primary winding, the third winding being in inductive relation to the load winding, and an auxiliary winding on the core in inductive relation to the primary winding and in series with the load winding, for the purpose described.
55 9. A constant potential transformer comprising in combination a closed magnetic core comprising first and second core portions, a primary winding on said first core portion adapted to be connected to a source of alternating current of fluctuating 60 voltage, a load winding on said second core portion and adapted to be connected to an output circuit, said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, a reso65 nant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding, and an auxiliary winding on said first core portion in inductive relation to the primary winding and in series with the load winding, the magnetic density at maximum predetermined input voltage of said first core portion being less thain the maximum density of said second core portion.

10. A constant potential transformer comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core provided with two leads and an intermediate tap, one of said leads and said tap leading to an output circuit, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining in said output circuit a substantially constant potential regardless of fluctuations in the input voltage cornprising a resonant circuit including a condenser connected in series between the leads of said second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding.
11. A constant potential transformer comprising in combination a magnetic core; a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage; a second winding on said core provided with two leads and an intermediate tap; said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion; and means for maintaining in said output circuit a substantially constant potential comprising a resonant circuit ineluding a condenser connected in series between the leads of the second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, and an auxiliary winding on said core in 40 inductive relation to the primary winding and in series with the load winding.
12. A constant potential transformer comprising in combination a closed magnetic core comprising first and second core portions; a primary 45 winding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage; a second winding on the second core portion and provided with two leads and an intermediate tap; one of said leadsandsaidtap 50 leading to an output circuit; said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion; the maximum density at maximum predetermined input voltage of said first 55 core portion being less than the maximum density of said second core portion; and means for maintaining in said output circuit a substantially constant potential comprising a resonant circuit including a condenser connected in series between 60 the leads of the second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, and an auxiliary winding on said core in inductive relation to the primary winding and o5 in series with the load winding.

JOSEPH G. SOLA.