DE1295730B - Process for the production of bistable thin-film toroidal cores - Google Patents

Description

The invention relates to a method for producing bistable thin-film toroidal cores.

The increased need for faster and more reliable computers is currently attracting interest Solid-state components directed. The development of the ferrite core represents a significant step The square loop characteristics of such cores are so uniform and reliable that computers with more than a million cores are operationally reliable. ίο

The development of thin-film elements for use in memories of digital computers was initiated by the desire to determine the ratio of the switching speed to the amplitude of the output signal of current ferrite core storage systems. The speed of work the memory was limited by the speed with which the magnetization between two die Information 1 and O representing stable states can be reversed.

There are two basic uses for thin-film toroidal cores, namely parallel and the orthogonal. With both types of use, the thin-film toroidal cores are arranged in a matrix, as is customary in data processing technology. It is possible to use the magnetic State of any selected toroid of the matrix individually by the simultaneous excitation a single row conductor and a single column conductor intersecting in this toroidal core change. When working in parallel, these conductors are excited in such a way that they generate parallel driving fields. On the other hand, in the orthogonal mode of operation, the conductors are connected in such a way that they have two driving fields at right angles to each other.

The parallel mode of operation is the mode of operation that is usually used in conjunction with ferrite toroidal cores is used. There are storage systems of this type for storing binary information Ducible properties can be generated. According to the invention, this object is achieved by the combination of the following Process steps solved:

a) Vacuum vapor deposition is applied to the outer surface of a hollow cylindrical silicon-containing carrier a layer of chromium or a chromium alloy is applied;

b) an electrically conductive layer of a noble metal is vapor-deposited onto this layer in a vacuum;

c) the electrically conductive layer is made by electrolytic deposition in a magnetic Directional field covered with a uniaxially oriented thin layer of a ferromagnetic metal;

d) the carrier with said coatings is embedded in a plastic mass;

e) the carrier including the embedding is in the radial direction in annular disks with parallel end faces cut up, and

f) the plastic mass is removed from the rings.

The thin-film toroidal cores produced by the process according to the invention can be used in the common parallel operating circuitry as an improved replacement for annular ferrite cores or in the newer orthogonal circuits. the Adaptation of the manufacturing process to the intended mode of operation of the toroidal cores gives the System in which these toroidal cores are used, excellent switching properties. Besides, it is very advantageous that thin-film toroidal cores cheap and in large quantities with the highest reliability and

can be produced in both three-dimensional and two-dimensional 40 uniform properties,
sional execution known. It is true in a known memory element

It is known, thin magnetic layers on a suitable carrier by known per se Process such as vapor deposition in a high vacuum, electrolytic deposition or sputtering, to be deposited. The fabrication of metal vapor deposition has received more attention than any of them two other manufacturing processes mentioned. In addition, it was almost the exclusive endeavor the magnetic layers on plan the process steps of vapor deposition of a conductive Layer on a support and covering this conductive layer with a ferromagnetic To find film by electrolytic deposition in a directional magnetic field, and also it is known to cut a ferrite strand into disks, but with these process steps the problem according to the invention cannot be achieved alone.

Carriers 50 So it is according to the inventive method

to deposit and a magnetic layer in a step d) absolutely necessary to the carrier with the

single deposition step to produce the said coatings prior to cutting into a

Storage of a large number of bits capable of embedding plastic mass, otherwise the very hard ones

is. and fragile cores damaged during cutting

One of the main problems of thin-film storage is 55 can be. The inventive method

in their manufacture. Method of manufacturing process step a) is necessary and contributes significantly

homogeneous and reproducible bistable thin-film storage elements large quantities have not yet been invented. So far, thin-film storage systems have only been built and tested on a trial basis. However, the reliability of the known ferrite core memory has not yet been achieved in thin-film memories reproduced.

It is thus the main object of the invention to provide a method for producing bistable thin-film toroidal cores to create a much lower switching constant than the current ferrite memory cores have and in large quantities with reprocessing solution of the problem according to the invention, since with the same the conductive layer mentioned in process step b) more firmly connected to the carrier will.

Details of the invention are given below with reference to the method examples shown in the figures and an embodiment of one with the thin-film toroidal core produced by the method described. It shows

F i g. 1 shows a thin-film toroidal core provided for the storage of a single bit in diagrammatic form Representation for orthogonal use,

3 4

F i g. 2 there is a diagram of the reading and writing effect of the process on the magnetic core

processes of the thin-film toroidal core according to FIG. 1, in it, after the signal "Write 0" in the O-state

F i g. 3 to leave a perspective section of the thin. The "Reading 0" process begins after

layer toroidal core according to FIG. 1, the application of another word current pulse. the

F i g. 4 is a diagram of the 5 Electroplating flow direction of the cylinder is changed H _w in time frame 4 by the Treibfür the implementation of the method for producing the same. Here, the dredes thin-film toroidal core is shown in FIG. 3, hung the direction of flow versus the rotation in

Figures 5A and 5B show the characteristic curves for time 1 reversed. The resulting initial one with the method according to the invention herimpuls indicates that a 0 has been read. This Provided thin film toroid for parallel Ar- io pulse is of opposite polarity too by way of example, during its production the orientation impulse, which at time 1 reads a 1 field was switched on for 90 ° / o of the electroplating time. At time 5, while the was, word stream is applied, additionally a negative bit

6A and 6B are the characteristic curves for current applied. The two driving fields H _b and H _w

with the method according to the invention, cause the rotation of the magnetization of the core

Provided thin-film toroidal core for orthogonal arnes against the 1-direction. On the removal of the

beitsweise, during the production of which the orientation word stream rotates the direction of flow in the

field switched on for 100% of the electroplating time, time 6 in the 1 state, that of the easy direction

was, and is closest. After this process »write 1«

F i g. 7 shows a diagram of various threshold values, 20 the core is again in the 1 state.

based on the duration of the deactivation of the Orien- Die F i g. 3 shows one according to the method according to FIG

tierungsstromes during the electrolytic Ab- the invention produced thin-film toroidal core,

divorce. as a direct replacement for ferrite cores in the

The F i g. 1 shows the for storing a parallel mode of operation or as a storage element in FIG

The structure used for the individual bits is useful when using the orthogonal mode of operation. Of the

orthogonal working method. The toroidal core represented by the toroidal core 8 consists of the short cylindrical

in which the magnetic flux along the substrate 10, which in Umdra contains silicon, is preferably made up

Light magnetizing glass running in the circumferential direction, the conductive metal layer 14, preferably

direction closes, lead two lines, one from gold, and the one essentially in the circumferential direction

sense line and a bit line. Electrolytically deposited ferro-

surface of the cylinder and at right angles to its magnetic alloy layer 16. When used

Axis are the two halves of a word line, made of gold as the conductive metal is between the glass

which form a loop around the cylinder. carrier 10 and the conductive gold layer 14 the ad-

The magnetic flux runs in the ortho-adhesive metal layer 12 made of chromium or its equivalent

gonally working bistable toroidal core to provide 35 valent. The adhesion of the gold layer

follow its preferred direction and the closed compared to the chrome is essentially better

Flow path in the circumferential direction. The heavy ma- than its adhesion to glass. The carrier has

The direction of magnetization runs parallel to the core axis and has a very small diameter. There were carriers

at right angles to the word line. One used by the latter where the ratio is inside diameter

flowing current drives the core flow in the heavy 40 to outer diameter about 0.51: 0.76, 0.64: 0.76,

Direction of magnetization, in which it was about 0.51: 0.64 and 0.38: 0.51 mm, and also

behaves unstably. The core flow seeks of course a smaller diameter are possible. The amount of the

of the two easy directions of magnetization, the toroidal core is very small and is preferably

to take. The polarity of the current is 2.5 mm or less.

through the bit line a complete control, 45 in order to achieve the desired toroidal core characteristics

where either the easy direction of magnetization is 1, the working process must be carefully

or the easy direction of magnetization 0 can be trolled out. The layer thicknesses and the orientation

is chosen. differentiation of the ferromagnetic layer

The writing and reading processes for the ortho are slightly for optimal results, depending on the gonal working method are shown in FIG. 2 shown. 5 ° whether the bistable core should work in orthogonal or par-At time 0, the core is in the "1" -allel mode of operation. The surface stand. The vertical structure of the silicon-containing tubular arrow indicating the direction of flow runs parallel to the easy direction of the Ma-carrier before the electrolytic deposition is of gnetisierung. Time 1 becomes very important because of the core. A stream of words must therefore be applied which brings about a change in the flux between the thickness of the conductive direction. The driving field H _w forms a right angle with the underlayer and the inherently desirable dimensional light direction. The change, for the purpose of reducing the flow direction, causes an output signal dense to make the underlayer as thick as possible in the sense line, and a "1" is read. The measures required for this have an effect. While the word stream remains applied, a bit 60 is therefore applied to the selection of the composition and the current pulse. This bit stream causes a thickness of the ferromagnetic layer along the tube, field H _b parallel to the easy direction of the core. shaped carrier. In this context, there are two driving fields at time 2, namely the adhesion of the conductive layer to the silicon H _b and H _w . The driving fields cause the rotatory girders to be particularly important,
Increasing the magnetization of the cylinder against the 65 The following is the procedure according to the Er-0 direction. When switching off the word stream finding described in detail,
the direction of flow rotates to the 0 state, and first of all, the adhesive layer in the vacuum results in an output pulse. The starting and the conductive layer are vapor-deposited. One tube

Silicon-containing material is thoroughly cleaned, dried and then placed in a vacuum evaporation chamber hooked. A layer of chrome or a layer of a chrome alloy is then applied for example of chromium and titanium, or of nickel and chromium, with a thickness of approximately 5 to 10 nm deposited on the outer surface of the support. Without interrupting the The vacuum is then applied to this metal layer

Stress reducing material. Boric acid is the preferred buffer. The inorganic chloride, which for example a sodium or potassium chloride promotes the dissolution of the anode in the case 5 detachable anodes and increases the conductivity of the bath. An example of the wetting agent is sodium lauril sulfate, which reduces the adhesion of the hydrogen bubbles to the cathode surface is used. The tension reliever

electrically conductive layer made of a noble metal is preferably saccharin, which is the mechanical

Stresses in the electrodeposition are reduced by a high percentage.

The bath composition and the electrolysis current density have a significant influence on

which closes the circuit via the conductor stretched through the cylinder to be electroplated.

The main difference between those following the orthogonal mode and those following the parallel one Wise working bistable toroidal cores is beyond the subtle differences between the thicknesses of the different layers the degree of alignment

steamed. The thickness of the conductive layer is within the range of 5 to 30 nm for the core operating in parallel. The core for that
orthogonal working method requires a precious metal,
such as gold or platinum, which has a thickness of 15 the iron content of the ferromagnetic lower than 500 nm, but preferably at one stroke. In those cases where the ferromagne thickness is between 50 and 150 nm, is vapor deposited. table precipitate should be a nickel-iron alloy Concentration of Fe ⁺ + ions in the bath increases the direct current and becomes layer than about 30 nm. The setting of the current density is however the 100 nanosecond pulse thresholds of the ring- preferred method for changing the alloy cores are very high and the rise time of the composition.

Characteristic curve of the cores is greatly reduced. The electroplating is carried out by the flow of current between

The characteristic curves of a toroidal core with a 25 see the cathode 22 and the anode 24 introduced, conductive underlayer of 10 to 20 nm thickness are The directional magnetic field is during the Galin 5 A and 5 B shown and are in their vanisierung by closing the switch 30-heights of the threshold value and the rise time are perfectly acceptable.

The conductive surface is now prepared for the electrolytic deposition of the ferromagnetic layer. The F i g. 4 shows schematically the electrical circuit of the device used for this purpose. The electrolyte 20 contains at least one dissolved salt of the

ferromagnetic metal to be deposited. The 35 of the ferromagnetic layer. In the case of the ortho-carrier with the conductive layer, whose ends work with gonal to obtain optimal ErSilber are closed, then in the electrical results a complete alignment of the ferrolytes used. The conductive layer is required for the magnetic layer in the circumferential direction 22 made of the electrolytic cell. The borrowed. Therefore it is used to manufacture toroidal cores for Anode 24 is then inserted into the cell. The 40 orthogonal operation of the directional magnetic field wäh-anode and the cathode is applied with the plus or end of the entire electroplating time. For Minus terminal of the power source 26 connected. However, the parallel working method was found Cathode is on the two ends of the conductive that the optimum is not through a completely in Layer connected to the power source 26, extending around the circumferential direction, but by a Uniformity of the galvanic deposit 45 against this slightly inclined orientation of the to improve. Provision is made while magnetic layer is achieved, the electroplating a magnetic directional field in this slightly inclined alignment can

Circumferential direction around the conductive support 22 can be achieved by that in the circumferential direction to put on. For this purpose, an electrical directional field is only available for a duration of Conductor is passed through the center of the cylinder and applied for 50-60 to 95% of the electroplating time, a further power source 28 is connected. The scarf is preferably either during the first ter30 is provided to generate the straightening field or during the last part of the galvanic ends Turning the power on and off. time remains switched off. It is not yet

The electrolytic bath can have a well-known certainty which orientation is in the have composition. The basic types 55 dejected shift during the period in which for galvanically deposited ferromagnetic the directional field is switched off, as well as during the Material are the sulphates, sulphamates, chlorides and transition from the deposition without directional field to a combination of sulfate and chloride baths. the one with a field running in the circumferential direction The names of the electrolytic baths are set by the. With certainty, however, can be assumed Name of the metal salt derived, which is to be supplied, that the wrung away without a magnetic field the required ferromagnetic ions in different sub-layers not in the circumferential direction Bath is used. are aligned. It can be assumed

The preferred bath, however, is the aqueous chloride - that the effective orientation of the electroplating bath, in which the ferromagnetic ions, such as precipitates, have a slight tendency towards Ni ⁺ + and Fe ++, by means of nickel and iron chlorides, assumes the orientation in the circumferential direction.

be brought to the solution. The other components of the bath include a buffer, an inorganic one Chloride, a wetting agent and a mechanical

In any case, the thin-film toroidal core produced by the method according to the invention is in its Switching properties essentially a magnetic core

consider, in its production, a circumferential direction during the entire electroplating time Directional magnetic field was applied when the core was working in a in the parallel manner Storage array is used.

A permalloy layer of approximately 75 to 82% nickel with the balance iron is the preferred ferromagnetic one Layer. The layer is with a preferred thickness between 1100 and 1500 nm for one core working in parallel and with a preferred thickness between 300 and 1200 nm for the orthogonal working method deposited. The diameter of the cylindrical support determines the Adjustment of the electroplating current to produce the desired layer thickness and composition.

Following the electroplating process, the hollow cylindrical ones provided with the layers mentioned can be used Carriers are subjected to various tests to ensure their usability and uniformity to ensure. The galvanized good parts are then arranged in rows, so that they are axially parallel to each other, and surrounded with a suitable potting compound to a to form solid block of embedded elongated parts. As soon as the potting compound has hardened, be the parts by means of a suitable cutting wheel into toroidal cores of about 2.5 mm or less cut. The potting compound is then removed and the toroidal cores can be tested for their task will. In this way, the problem of achieving uniformity and reliability becomes a storage system containing a large number of storage cores solved.

Bistable toroidal cores for parallel operation can be made using a glass tube with a Inside diameter of 0.5 mm, an outside diameter of 0.63 mm and a height of 0.5 mm. with the following properties:

40 Reading current l _r 700 mA ± 10 ° / o

Pulse duration T _d 75 ns

Word current l _r 250 mA ± 10%

Pulse duration T _d 100 ns

Bit stream l _b 140 mA ± 10%

Pulse duration T _d 125 ns

45 of 2mm easily obtained with the following properties for a rise time of T ^ = 20 nanoseconds:

Word stream / _r 800 mA

Bit stream I _b 225 mA

Switching time 10 to 20 ns

Switching constant 0.01 Oe μβ

Sense output ± 10 mV

The switching time and the sampling output are directly dependent on the rise time T _R and are increased with shorter rise times.

The following examples are provided to facilitate understanding of the invention, and are various changes are possible within the scope of the invention.

example 1

The bistable toroidal cores operating in the parallel manner were illustrated by the following Process made. A glass tube with an outside diameter of 0.7mm, an inside diameter of 0.5 mm and a length of 76 mm was thoroughly cleaned and dried. The tube was placed in a normal vacuum evaporation chamber and on its outer surface with coated with a layer of chromium with a thickness of 5 to 10 nm. Immediately thereafter was followed without breaking the vacuum, a layer of gold is vapor-deposited onto the chrome layer until a Square resistance of 2.5 ohms was reached, which corresponds to a thickness of the gold layer of 10 to approximately Corresponds to 20 nm.

The cylindrical glass substrate with the conductive gold layer on its outer surface was attached to its Ends closed with silver, hung in an electrolytic cell and connected to the conductive layer made on each end of the tube to the cathode of the cell. The Elektmly ^ mTleF-J cell contained the following ingredients in an aqueous solution:

Nickel chloride (NiCl ₂ · 6H ₂ O) 194 g / l

Ferric chloride (FeCl ₂ -4 H ₂ O) 7.85 g / l

Sodium chloride (NaCl) 9.7 g / l

Bias current I _c 47.5 mA + 5%

Reading fault 60 mA

Pulse duration T ₀ 100 ns

Time constant 30 ns

Read off »0«, dV _z 6 mV

Switching time T _s 45 to 60 ns

Read »1«, dV _x 20 mV

Coercive field strength 0.5 Oe

Switching constant 0.02 to 0.03 Oe μβ

Magnetic cores with the values dV ₁ = 37 mV and dV _z − 4 mV were obtained by the method according to the invention. The low value 0.007 Oe · μ5 was achieved for the switching constant.

Bistable toroidal cores for orthogonal operation were made using a glass tube with an inner diameter of 0.38 mm, an outer diameter of 0.64 mm and a height

Boric acid (H ₃ BO ₃ ) 25 g / l

Saccharin lg / 1

Sodium lauril sulfate 0.42 g / l

An electrical conductor was stretched through the cylindrical carrier before it was closed with silver and, as shown in FIG. 4, connected to the power source 28 via the switch 30. This circuit, which generates the directional magnetic field, was designed for a current of 2.5 A. This 2.5 A current flowing through the conductor generated a magnetic field running around the conductor with a field strength of 13 Oe on the surface of the glass tubes. The temperature of the electrolyte was kept at 33.1 ± 0.1 ° C and the pH at 3.2 ± 0.1. A plating current of 4.1 mA / cm ²

was passed over the cathode and anode for 20 minutes. Only after the first The magnetic directional field was switched on for 2 minutes of electroplating. The resulting lower

909 521/117

Claims (16)

impact had a thickness of approximately 1200 to 1300 nm with a composition of approximately 80% nickel and 20% iron. The galvanized cylindrical body was poured into a mixture of rosin (60%) and paraffin (40%), which then solidified. The cast-in galvanized body was then cut into parts with a height of 0.5 mm in a plane perpendicular to its longitudinal axis by means of a diamond cutting wheel. Each of these 0.5 mm long parts can be used as a bistable closed magnetic core after the potting compound has been removed. The complete characteristic curves shown in FIGS. 5A and 5B were obtained for a bistable toroidal core produced according to the example given. The characteristic curves were obtained by progressively increasing the current flow in a conductor stretched through the center of the magnetic core and by recording the resulting magnetic flux. In each figure ao, the part of the characteristic curve referred to as the direct current curve was obtained by a 60-period current through the conductor that appears to be direct current compared to the 100 nanosecond current. The 100 nanosecond pulse waveform was obtained when 100 nanosecond pulses passed through the conductor. Example 2 Example 1 was repeated with the exception that the orientation field was now switched on for the entire duration of the electroplating. The characteristic curves resulting for a toroidal core produced according to this example are shown in FIGS. 6A and 6B. From a comparison of the characteristic curves in FIGS. 5A, 5B and 6A and 6B, it can be seen that the DC curve parts in FIGS. 5 and 5 remain the same. The 100 nanosecond curves in FIGS. 5A and 5B_jeixeicJhejiJeiioifc wiei? Scnellei · __üirejnaximum magnetic flow values as the corresponding curve parts in FIGS Invention generated magnetic cores required switching time is significantly less than for those cores in whose generation the current generating the directional field was switched on for 100% of the electroplating time. The shorter switching time of the magnetic cores when they work in parallel can be attributed to 5 "of the torque , which is caused by the assumed slight inclination of the orientation in the ferromagnetic layer relative to the circumferential direction. The curves in FIG. 7 show the relationship between the switch-off duration of the magnetic directional field during the constant electroplating time and the 100 nanosecond switchover threshold value and the direct current threshold value. The direct current threshold value remains constant over the entire test. It can be seen from the curve, however, that the level of the 100 nanosecond switchover threshold value is reduced if the directional field running in the circumferential direction is switched off during part of the electroplating time. If the thickness of the layer deposited without a directional field and therefore not oriented is increased in relation to the thickness of the preferentially oriented layer, the total output power of the magnetic core is reduced. Furthermore, the hysteresis loop of the magnetic toroidal core tends to be constricted as the thickness of the unoriented layer increases. It has been found that the combination of oriented and unoriented galvanic layers, generated with an orientation current switched on for 60 to 95% of the galvanizing time, results in bistable toroidal cores with the best properties for use in parallel operation. The switching constants of these bistable thin-film toroidal cores according to the invention are 5 to 10 times smaller than those of ferrite cores under the same field conditions. Example 3 The following procedure was used to make bistable toroidal cores for orthogonal operation. The procedure used for example 3 was similar to the procedure of example 1, with the following important differences: A much thicker gold layer of 100 nm was evaporated onto the chromium layer by evaporating a larger amount of gold in the vacuum evaporation system and depositing it on the carrier. The plating time, expressed in mA · min, was reduced to half that used for a core for parallel operation, and a deposit of 600 nm was deposited on the conductive gold layer. The directional magnetic field in the circumferential direction was switched on during the entire electroplating time. The bistable toroidal cores produced by this method for the orthogonal mode of operation fully meet the requirements specified above. , ^ ---- - claims: 1. Process for the production of bistable thin-film toroidal cores, characterized by the combination of the following process steps: a) On the outer surface of a hollow cylindrical silicon-containing carrier (10) is means A layer (12) of chromium or a chromium alloy is applied by vacuum vapor deposition; b) on the layer (12) is an electrically conductive layer (14) of a noble metal in Vacuum deposited; c) the electrically conductive layer (14) is by electrolytic deposition in one magnetic directional field with a uniaxially oriented thin layer (16) of a ferromagnetic Metal plated; d) the carrier with said coatings is embedded in a plastic mass; e) the carrier including the embedding is in the radial direction in annular disks with parallel Cut end faces, and f) the plastic mass is removed from the rings. 2. The method according to claim 1, characterized in that the under the electrically conductive Layer (14) located layer (12) 5 to 10 nm thick and made of a chromium-titanium alloy. 3. The method according to claim 1, characterized in that the under the electrically conductive Layer (14) located layer (12) is 5 to 10 nm thick and made of a nickel-chromium alloy consists. 4. The method according to claim 1, characterized in that the conductive layer (14) at Toroidal cores intended for parallel operation are given a thickness of 5 to 30 nm. 5. The method according to claim 1, characterized in that the conductive layer (14) at Toroidal cores intended for orthogonal operation have a maximum thickness of 500 nm, preferably is given in the range from 50 to 150 nm. 6. The method according to claim 1, characterized in that the ferromagnetic layer (16) deposited in an electrolyte with at least one salt of the ferromagnetic metal ao is, wherein the conductive layer (14) serves as a cathode (22) of the electrolytic cell and a through the hollow cylindrical carrier (10) passed electrical conductor to an additional, controllable power source (28) is connected. 7. The method according to claim 1, characterized in that the ferromagnetic metal a nickel-iron alloy is used. 8. The method according to claim 1, characterized in that when certain for parallel operation Toroidal cores as a ferromagnetic metal layer Permalloy with about 75 to 82% nickel content with a layer thickness of 1.1 to 1.5 μΐη is used. 9. The method according to claim 1, characterized in that when certain for orthogonal operation Toroidal cores as a ferromagnetic metal layer Permalloy with about 75 to 82% nickel content with a layer thickness of 0.3 to 1.2 μπι is used. 10. The method according to claim 1, characterized in that the carrier (10) is a glass tube with an inside diameter of about 0.5 mm, an outside diameter of about 0.64 mm and a height of about 0.5 mm is used if the toroidal cores produced are intended for parallel operation are. 11. The method according to claim 1, characterized in that that as a carrier (10) a glass tube with an inner diameter of about 0.38 mm, an outer diameter of about 0.64 mm and a height of about 2.0 mm is used if the manufactured toroidal cores are intended for orthogonal operation are. 12. The method according to claim 6, characterized in that when certain for orthogonal operation Toroidal cores of the conductors passed through the carrier (10) during the entire electroplating to the additional power source (28) is connected. 13. The method according to claim 6, characterized in that when certain for parallel operation Toroidal cores of the conductor passed through the carrier (10) during 60 to 95% of the time Electroplating time is connected to the additional power source (28). 14. The method according to claim 13, characterized in that the power source (28) during of the first part or during the last part of the electroplating is switched off. 15. The method according to claim 6, characterized in that the electrolyte to about 33 ° C is maintained at a pH of about 3.2. 16. The method according to claim 1, characterized in that the plastic mass consists of a Mixture consists of rosin and paraffin. 1 sheet of drawings