CA2026136A1 - Pulse transformer - Google Patents
Pulse transformerInfo
- Publication number
- CA2026136A1 CA2026136A1 CA002026136A CA2026136A CA2026136A1 CA 2026136 A1 CA2026136 A1 CA 2026136A1 CA 002026136 A CA002026136 A CA 002026136A CA 2026136 A CA2026136 A CA 2026136A CA 2026136 A1 CA2026136 A1 CA 2026136A1
- Authority
- CA
- Canada
- Prior art keywords
- core
- transformer
- primary
- secondary winding
- winding
- 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.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F19/00—Fixed transformers or mutual inductances of the signal type
- H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
- H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2847—Sheets; Strips
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Coils Or Transformers For Communication (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
Abstract The invention relates to a pulse transformer for the transformation of low voltage pulses to high voltage pulses with an extremely high step-up ratio. This is achieved by the use of a magnetic core (7) that is connected to the high voltage lead (23) and by a primary winding (8), at least partially surrounding the secondary winding (9), used to clamp the pulse transformer to an electrically conducting plate (18).
Description
2 ~
Pulse ~ransformer The invention relates to a pulse transformer for the transformation of low-voltage pulses to high-voltage pulses, whlch is equipped with a primary winding suitable for connection to a pulS8 transformer generating low-voltage pulses, a secondary winding provided with high-voltage terminals, snd a transformer core, which is at least partly surrounded by the primary and secondary windings.
This type of pulse transformer can be used in a radar transmitter for the generation of radar transmit pulses. The transformer is then placed between a pulse forming network and a high power tube, such as a magnetron or a klystron. In that application, the transformer :"
- is required to transform voltage pulses, generated by the pulse forming network, of e.g. several hundred volts, thousands of amperes and a length in the order of microseconds, to voltage pulses of tens of kilovolts and tens of amperes. The transformed pulses are applied to the klystron or magnetron for the generation of microwave pulses.
r~ These microwave pulses must be generated at a certain repetition rate, the intervals between consecutive pulses being used by a radar receiver to collect echoes of emittted pulses. However, to enable an echo to be received immediately after the emission of a pulse, the pulses need to have steep etg-s.
Pulses having less steep edges may be caused by what is known as the leakage inductance of the pulse transformer. This occurs if the coupling between the primary and 4econdary winting of the ;~30 transformer is less than optimal. Then, the electromagnetic fields ~` generated by the primsry and secondary windings are not fully coupled.
2 $ ~
Supply leads, too, may contribute to the leakage intuctance, as well as ths non-conducting spacing which, to achieve the necessary insulation, is present between wind$ngs and core.
From GB-A 2.103.426 a version of this type of pulse transformer is known, which is equippet with a toroidal core around which is wound a secondary toroidal winding, the primary winding completely surrounding this sccondary winding, from which it is separated by an abundance of insulation material.
,-. .
A toroital core with toroidal windings around it will keep the magnetic flus mainly contained within the core. A disadvantage is that much interspace is needet for the insulation between the primary and secondary wintings, the insulation space in turn having an adverse effect on the coupling between the wintings.
`: :
The pulse transformer according to the invention has for its ob~ect to provite a transformer exhibitlng little leakage inductance by limiting to a large extent the spacing between the windings and between windings and core. To this end ehe pulse transformer is equipped with connection means between the secondary winding and the transformer core for connecting the high voltage to the transformer core, the secondary winding, for at least part of its width, being surrounded by the entire primary winding.
25`~
Since now the voltage on the~transformer core closely follows the voltage on the secondary winding, little or no insulation is needed ;~
between the secondary winding and the core. This results in a better coupl:ing and less leakage inductance.
In one embodiment of the pulse transformer featuring a primary winding in the form of a foil with conductive material, wound arount a secondary winding which is al80 in the form of a conducting foil, ~ the potential difference between successive layers is small.
'~
~63 h ~
Conssquently, the required insulation space between the windings is minimal, further reducing the leakage inductance.
A further reduction of the leaksge inductance is achieved in an embodiment where the transformer core is clamped, by means of the primary winding, to an electrically conducting support frame which comprises insulated parts, a current supplying part and a current draining part having a contact surface with, respectively, the conducting side of a current supplying lead and a current draining lead of the primary winding. Consequently, the space between the primary and secondary windings can be limited to a minimum and a well-defined electrical connection i8 obtained.
~;~ The invention will be elucidated with reference to the accompanying ; 15 drawings, of which:
Fig. 1 shows a partial circuit diagram of a radar transmitter with pulse trsnsformer;
Fig. 2 shows a schematic embodiment of a pulse transforDer with -~ support; and Fig- 3 shows a schematic side view of the windings and core of the `~ pulse transformer of Fig. 2 in the direction of the line A-A.
The pulse transformer according to the invention can be used in a radar transmit chain as tepicted schematically in Fig. 1. A pulse generator 2, connected to power supply 1, generates pulses with a length and at a repetition rate which are suitable for ratar. To this end, the pulse generator 2 comprises known pulse forming means, such as networks incorporating delay lines, and switching means using, e.g. thyristors. The generated pulses are appliet in the ~ 30 usual ~ay via a fast saturable coil 3 to the pulse transformer 4.
The coil 3 blocks the pulses until the switching means in the pulse generator 2 have become fully conductive, to prevent power loss across the switching means.
' iJ~
Q ~ 7 r~
The pulses applied to tha pulse transformer 4 have characteristic pulse lengths of about 1 ~s, characteristic peak voltages of about 400 V and characteristic peak currents of about 8000 A.
The pulse transformer 4 transforms these low-voltage pulses to high-voltage pulses with characteris~ic peak voltages of 80 kV ant peak currents of 40 A. The achieved transformation ratio ~s thus 1 : 200 in this case, which is considerably higher than customary for pulse transformers. The high-voltage pulses are subsequently applied to a radar transmitter 5, provided with ia high power tube, such as a magnetron or klystron, which on the basis of the applied pulses generates microwave pulses with corresponding pulse lengths.
Finally, the microwave pulses are emitted by an antenna 6.
An embodiment of the pulse transformer according to the invention, illustrated in Fig. 2, comprises a transformcr core 7, primary windings B and secondary windings 9. The transformer core 7, for which conventional material is used, is built up from two tightly ~ Joined U-shaped parts forming a magnetic circuit, on two facing `~ ~ parts of which the windings 8 iand 9 have been mounted. The core may also be E-shaped, however, with a primary and secondary winding - ~ wound around all three core legs, or ~-shaped with a primary and ~ -secondary winding on only one leg. The principal point is that `~; ~ primary winding 8 ~hould enclose the secondary winding as tightly as possible, to achieve a proper couping.
To this end the primary winding 8, vhich in this case i8 in the ,form of a foil, is clamped through connections 13, 14, 15 to a ~;~ support frame consisting of three part~ 10, 11 and 12. The parts 10, 11 and 12 of the s~pport frame are made from electrically conducting material, the part 12 being electrically insulated from the parts 10 ` and 11 b~ an insulating layer 16. Part 12 makes electrical contact with a part of the electrically conducting side of the primary winding 8, which part is clamped by the connection 14. The side of the primary winding 8 adJoining the transformer core 7 is not provided with an insulating layer.
:
2 ~ 2 ~
The parts 10 and 11 make electrlcal contact with the leats of the primary winding 8 which are clamped by the connections 13 and 15.
The parts 10 and 11 are subsequently connected electrically, through connections 17, to a conducting plate 18. The part 12 protrutes through an opening of the plate 18, and is clamped on the opposite site of it through connections 19 and 20. Between the part 12 and the plate 18 a foil 21 is inserted, with two conductive sides which ; are separated b~ an insulation layer. The foil 21 is connected to the pulse generator 2 via the saturable coil 3. The primary current path then runs via the side of the foil 21 which makes contsct with the part 12, the part 12 proper, the primary winding 8, the parts 10 and 11, the plate 18 and tha side of the foil 21 which makes contact with plate 18. Between the plate 18 and part 12 there is further the - coil 3.
The primary winding 8 i8 prefsrably a foil w~th on one side a contuct~ng layer. The advantage is that the potential differences between the layers remain limitet to, in this csse, 400 V per layer.
Consequently little space is needed for inter-layer insulation and the arrangement can be quite compact, ~hich has a favourable effect on the leakage inductance and the coupling. The parts of the ~ secondary ~inding 9 which are nearest to the primary winding 8 and ¦ ~; those which are nearest to the transformer core 7 are providad with low-voltage leads 22 and high-voltage leads 23, respectively, such that tbey are e~ternally connectable. The high-voltage leads 23 are electrically linked to the transformer core 7 through a ~ core-surrounding clamping ring 24. The secondary winding 9 is wound -Y~ on a coil former (not shown in the figure), which freely surrounds -~ the transformer core 7. One of the high-voltage leads 23 i8 connected to the core 7 by way of an AC coupling in the form of capacitor 25, which forms a low impedance to the generated pulses but, conversely, a high one to a low-frequency AC voltage, applied in the customary manner across the secondary w~nding 9, to power the filament of a high power tube, when connected.
~2~
It should ba noted that there are tifferent ways in which the core 7 can be elactrically linked with the secondary winding. In an alternative embodiment, for instance, part of the secondary winding 9 is wound directly on the core 7, no coil former being used in this case.
In yet another embodiment, the secontary winding 9 may take the form of a wire winding, but then more space will be needed for insulation.
,~ 10 Flg. 3 is a side view of the pulse transformer according to the line A-A in Fig. 2. The low-voltage leads 22 are kept as far as possible removed from the transformer core 7. The ratio between the width of the primary winding 8 and the width of the secontary winting 9 determines the transformer characteristics to 8 consiterable estent.
Preferably, the secondary winding 9 i8 mad~ wider than the primary w~nding 8.
~; ~
;~ 30 ~ .
~ik~
Pulse ~ransformer The invention relates to a pulse transformer for the transformation of low-voltage pulses to high-voltage pulses, whlch is equipped with a primary winding suitable for connection to a pulS8 transformer generating low-voltage pulses, a secondary winding provided with high-voltage terminals, snd a transformer core, which is at least partly surrounded by the primary and secondary windings.
This type of pulse transformer can be used in a radar transmitter for the generation of radar transmit pulses. The transformer is then placed between a pulse forming network and a high power tube, such as a magnetron or a klystron. In that application, the transformer :"
- is required to transform voltage pulses, generated by the pulse forming network, of e.g. several hundred volts, thousands of amperes and a length in the order of microseconds, to voltage pulses of tens of kilovolts and tens of amperes. The transformed pulses are applied to the klystron or magnetron for the generation of microwave pulses.
r~ These microwave pulses must be generated at a certain repetition rate, the intervals between consecutive pulses being used by a radar receiver to collect echoes of emittted pulses. However, to enable an echo to be received immediately after the emission of a pulse, the pulses need to have steep etg-s.
Pulses having less steep edges may be caused by what is known as the leakage inductance of the pulse transformer. This occurs if the coupling between the primary and 4econdary winting of the ;~30 transformer is less than optimal. Then, the electromagnetic fields ~` generated by the primsry and secondary windings are not fully coupled.
2 $ ~
Supply leads, too, may contribute to the leakage intuctance, as well as ths non-conducting spacing which, to achieve the necessary insulation, is present between wind$ngs and core.
From GB-A 2.103.426 a version of this type of pulse transformer is known, which is equippet with a toroidal core around which is wound a secondary toroidal winding, the primary winding completely surrounding this sccondary winding, from which it is separated by an abundance of insulation material.
,-. .
A toroital core with toroidal windings around it will keep the magnetic flus mainly contained within the core. A disadvantage is that much interspace is needet for the insulation between the primary and secondary wintings, the insulation space in turn having an adverse effect on the coupling between the wintings.
`: :
The pulse transformer according to the invention has for its ob~ect to provite a transformer exhibitlng little leakage inductance by limiting to a large extent the spacing between the windings and between windings and core. To this end ehe pulse transformer is equipped with connection means between the secondary winding and the transformer core for connecting the high voltage to the transformer core, the secondary winding, for at least part of its width, being surrounded by the entire primary winding.
25`~
Since now the voltage on the~transformer core closely follows the voltage on the secondary winding, little or no insulation is needed ;~
between the secondary winding and the core. This results in a better coupl:ing and less leakage inductance.
In one embodiment of the pulse transformer featuring a primary winding in the form of a foil with conductive material, wound arount a secondary winding which is al80 in the form of a conducting foil, ~ the potential difference between successive layers is small.
'~
~63 h ~
Conssquently, the required insulation space between the windings is minimal, further reducing the leakage inductance.
A further reduction of the leaksge inductance is achieved in an embodiment where the transformer core is clamped, by means of the primary winding, to an electrically conducting support frame which comprises insulated parts, a current supplying part and a current draining part having a contact surface with, respectively, the conducting side of a current supplying lead and a current draining lead of the primary winding. Consequently, the space between the primary and secondary windings can be limited to a minimum and a well-defined electrical connection i8 obtained.
~;~ The invention will be elucidated with reference to the accompanying ; 15 drawings, of which:
Fig. 1 shows a partial circuit diagram of a radar transmitter with pulse trsnsformer;
Fig. 2 shows a schematic embodiment of a pulse transforDer with -~ support; and Fig- 3 shows a schematic side view of the windings and core of the `~ pulse transformer of Fig. 2 in the direction of the line A-A.
The pulse transformer according to the invention can be used in a radar transmit chain as tepicted schematically in Fig. 1. A pulse generator 2, connected to power supply 1, generates pulses with a length and at a repetition rate which are suitable for ratar. To this end, the pulse generator 2 comprises known pulse forming means, such as networks incorporating delay lines, and switching means using, e.g. thyristors. The generated pulses are appliet in the ~ 30 usual ~ay via a fast saturable coil 3 to the pulse transformer 4.
The coil 3 blocks the pulses until the switching means in the pulse generator 2 have become fully conductive, to prevent power loss across the switching means.
' iJ~
Q ~ 7 r~
The pulses applied to tha pulse transformer 4 have characteristic pulse lengths of about 1 ~s, characteristic peak voltages of about 400 V and characteristic peak currents of about 8000 A.
The pulse transformer 4 transforms these low-voltage pulses to high-voltage pulses with characteris~ic peak voltages of 80 kV ant peak currents of 40 A. The achieved transformation ratio ~s thus 1 : 200 in this case, which is considerably higher than customary for pulse transformers. The high-voltage pulses are subsequently applied to a radar transmitter 5, provided with ia high power tube, such as a magnetron or klystron, which on the basis of the applied pulses generates microwave pulses with corresponding pulse lengths.
Finally, the microwave pulses are emitted by an antenna 6.
An embodiment of the pulse transformer according to the invention, illustrated in Fig. 2, comprises a transformcr core 7, primary windings B and secondary windings 9. The transformer core 7, for which conventional material is used, is built up from two tightly ~ Joined U-shaped parts forming a magnetic circuit, on two facing `~ ~ parts of which the windings 8 iand 9 have been mounted. The core may also be E-shaped, however, with a primary and secondary winding - ~ wound around all three core legs, or ~-shaped with a primary and ~ -secondary winding on only one leg. The principal point is that `~; ~ primary winding 8 ~hould enclose the secondary winding as tightly as possible, to achieve a proper couping.
To this end the primary winding 8, vhich in this case i8 in the ,form of a foil, is clamped through connections 13, 14, 15 to a ~;~ support frame consisting of three part~ 10, 11 and 12. The parts 10, 11 and 12 of the s~pport frame are made from electrically conducting material, the part 12 being electrically insulated from the parts 10 ` and 11 b~ an insulating layer 16. Part 12 makes electrical contact with a part of the electrically conducting side of the primary winding 8, which part is clamped by the connection 14. The side of the primary winding 8 adJoining the transformer core 7 is not provided with an insulating layer.
:
2 ~ 2 ~
The parts 10 and 11 make electrlcal contact with the leats of the primary winding 8 which are clamped by the connections 13 and 15.
The parts 10 and 11 are subsequently connected electrically, through connections 17, to a conducting plate 18. The part 12 protrutes through an opening of the plate 18, and is clamped on the opposite site of it through connections 19 and 20. Between the part 12 and the plate 18 a foil 21 is inserted, with two conductive sides which ; are separated b~ an insulation layer. The foil 21 is connected to the pulse generator 2 via the saturable coil 3. The primary current path then runs via the side of the foil 21 which makes contsct with the part 12, the part 12 proper, the primary winding 8, the parts 10 and 11, the plate 18 and tha side of the foil 21 which makes contact with plate 18. Between the plate 18 and part 12 there is further the - coil 3.
The primary winding 8 i8 prefsrably a foil w~th on one side a contuct~ng layer. The advantage is that the potential differences between the layers remain limitet to, in this csse, 400 V per layer.
Consequently little space is needed for inter-layer insulation and the arrangement can be quite compact, ~hich has a favourable effect on the leakage inductance and the coupling. The parts of the ~ secondary ~inding 9 which are nearest to the primary winding 8 and ¦ ~; those which are nearest to the transformer core 7 are providad with low-voltage leads 22 and high-voltage leads 23, respectively, such that tbey are e~ternally connectable. The high-voltage leads 23 are electrically linked to the transformer core 7 through a ~ core-surrounding clamping ring 24. The secondary winding 9 is wound -Y~ on a coil former (not shown in the figure), which freely surrounds -~ the transformer core 7. One of the high-voltage leads 23 i8 connected to the core 7 by way of an AC coupling in the form of capacitor 25, which forms a low impedance to the generated pulses but, conversely, a high one to a low-frequency AC voltage, applied in the customary manner across the secondary w~nding 9, to power the filament of a high power tube, when connected.
~2~
It should ba noted that there are tifferent ways in which the core 7 can be elactrically linked with the secondary winding. In an alternative embodiment, for instance, part of the secondary winding 9 is wound directly on the core 7, no coil former being used in this case.
In yet another embodiment, the secontary winding 9 may take the form of a wire winding, but then more space will be needed for insulation.
,~ 10 Flg. 3 is a side view of the pulse transformer according to the line A-A in Fig. 2. The low-voltage leads 22 are kept as far as possible removed from the transformer core 7. The ratio between the width of the primary winding 8 and the width of the secontary winting 9 determines the transformer characteristics to 8 consiterable estent.
Preferably, the secondary winding 9 i8 mad~ wider than the primary w~nding 8.
~; ~
;~ 30 ~ .
~ik~
Claims (6)
1. Pulse transformer for the transformation of low-voltage pulses to high-voltage pulses which transformer is provided with a primary winding suitable for connection to a pulse generator generating low-voltage pulses, a secondary winding provided with high-voltage terminals, a transformer core which is at least partly surrounded by the primary and secondary windings, and connection means between the secondary winding and the transformer core for connecting the high voltage to the transformer core, the secondary winding, for at least part of its width, being surrounded by the entire primary winding.
2. Pulse transformer according to claim 1, wherein said connection means is provided with a flexible conductor between the transformer core and a high-voltage terminal.
3. Pulse transformer according to claim 1, wherein said connection means comprise part of the secondary winding which is in contact with the transformer core.
4. Pulse transformer according to one of the claims 1 to 3, wherein the primary winding takes the form of a conducting foil, wound around a secondary winding, also in the form of a conducting foil.
5. Pulse transformer according to one of the foregoing claims, wherein said transformer core comprises two butt-jointed U-shaped core parts, and two facing core pieces of the transformer core are each surrounded by a primary and a secondary winding, the primary and secondary winding, respectively, of one core piece being connected to the primary and secondary winding, respectively, of the other core piece.
6. Pulse transformer according to claim 4 or 5, wherein the transformer core is clamped, by means of the primary winding, to an electrically conducting support frame which comprises insulated parts, a current supplying part and a current draining part having a contact surface with, respectively, the conducting side of a current supplying lead and a current draining lead of the primary winding.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8902474A NL8902474A (en) | 1989-10-05 | 1989-10-05 | PULSE TRANSFORMER. |
| NL8902474 | 1989-10-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2026136A1 true CA2026136A1 (en) | 1991-04-06 |
Family
ID=19855402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002026136A Abandoned CA2026136A1 (en) | 1989-10-05 | 1990-09-25 | Pulse transformer |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0421514A1 (en) |
| JP (1) | JPH03171706A (en) |
| KR (1) | KR910008754A (en) |
| AU (1) | AU6370290A (en) |
| CA (1) | CA2026136A1 (en) |
| NL (1) | NL8902474A (en) |
| NO (1) | NO904311L (en) |
| PT (1) | PT95391A (en) |
| TR (1) | TR25672A (en) |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB204474A (en) * | 1922-08-16 | 1923-10-04 | Veifa Werke Ag | Improvements in or relating to high tension electric transformers |
| GB766946A (en) * | 1953-12-12 | 1957-01-30 | Philips Electrical Ind Ltd | Improvements in or relating to high-voltage transformers |
| US2998583A (en) * | 1956-02-13 | 1961-08-29 | Willis G Worcester | Electrical apparatus and electromagnetic coils and method of making the same |
| GB940500A (en) * | 1959-12-02 | 1963-10-30 | Noel Ebenezer Morris Brydon | Improvements relating to the construction of underground buildings |
| US3184893A (en) * | 1960-04-11 | 1965-05-25 | Contact Foundation Inc | Contact foundation method |
| US3617854A (en) * | 1970-04-20 | 1971-11-02 | Raytheon Co | Pulse transformer |
| DE2406693C3 (en) * | 1974-02-13 | 1981-01-22 | Benteler-Werke Ag Werk Neuhaus, 4790 Paderborn | Device for the transmission of direct current of high amperage and low harmonics to the rotating electrode disk during roller seam resistance butt welding |
| GB2103426B (en) * | 1981-08-08 | 1985-02-06 | Marconi Co Ltd | Transformers |
| DE3534006A1 (en) * | 1985-09-24 | 1987-03-26 | Siemens Ag | Pulse transformer |
| SE469726B (en) * | 1990-04-30 | 1993-08-30 | Outokumpu Oy | VERTICAL PILLAR BREAKING PROVIDING UPPER DOWN |
-
1989
- 1989-10-05 NL NL8902474A patent/NL8902474A/en not_active Application Discontinuation
-
1990
- 1990-09-24 PT PT95391A patent/PT95391A/en not_active Application Discontinuation
- 1990-09-25 EP EP90202532A patent/EP0421514A1/en not_active Withdrawn
- 1990-09-25 CA CA002026136A patent/CA2026136A1/en not_active Abandoned
- 1990-09-26 KR KR1019900015270A patent/KR910008754A/en not_active Application Discontinuation
- 1990-09-28 TR TR90/0893A patent/TR25672A/en unknown
- 1990-10-02 AU AU63702/90A patent/AU6370290A/en not_active Abandoned
- 1990-10-02 JP JP2263218A patent/JPH03171706A/en active Pending
- 1990-10-04 NO NO90904311A patent/NO904311L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NL8902474A (en) | 1991-05-01 |
| TR25672A (en) | 1993-07-01 |
| KR910008754A (en) | 1991-05-31 |
| NO904311D0 (en) | 1990-10-04 |
| JPH03171706A (en) | 1991-07-25 |
| PT95391A (en) | 1992-05-29 |
| EP0421514A1 (en) | 1991-04-10 |
| AU6370290A (en) | 1991-04-11 |
| NO904311L (en) | 1991-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2216524A1 (en) | Electric arc detector sensor circuit | |
| US10050533B2 (en) | High voltage high frequency transformer | |
| NZ201175A (en) | Switched mode power supply transformer with windings in alternate slot | |
| EA199900702A1 (en) | POWERFUL TRANSFORMER OR INDUCTANCE COIL | |
| RU2388092C2 (en) | Pulse transformer with foil winding | |
| JP2008518515A (en) | Inductive coupling device for data communication | |
| US6950291B1 (en) | Electromagnetic interference shielding for small magnetic devices | |
| US4527098A (en) | Discrete starter for HID lamp | |
| CA2095792A1 (en) | Switchable inductor for strong currents | |
| TR199901585T2 (en) | G�� transformat�r� /ind�kleyicisi | |
| US3514566A (en) | Adjustable voltage transformer for microwave oven apparatus | |
| CA2026136A1 (en) | Pulse transformer | |
| RU2108649C1 (en) | Method and device for feeding electrical equipment | |
| ES2139507A1 (en) | Hyperthermia device | |
| US1676680A (en) | System for the electric transmission of signals along lines for power distribution | |
| US5489825A (en) | Transformer | |
| US20220108829A1 (en) | Wire for use in transformer winding and transformer | |
| JPH01305603A (en) | Line transformer | |
| US4320373A (en) | Power transformer with high coupling coefficient | |
| JPS62111529A (en) | Signal transmission equipment utilizing low voltage distribution line | |
| RU2122760C1 (en) | Transformer unit | |
| RU94021986A (en) | WINDING OF HIGH-FREQUENCY KUPRIANANE ELECTROMAGNETIC DEVICE E.G. | |
| JPH1168498A (en) | Impedance transformation circuit | |
| JPS6431374A (en) | High-frequency heating device | |
| CA2172102A1 (en) | Radio frequency choke for telecommunications transmission |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |