DE1022273B - Mains connection rectifier circuit for wireless communication technology devices - Google Patents

Description

GERMAN

Mains connection rectifier circuit for wireless communications equipment

Applicant:
North German Mende-Rundfunk G. mb H.,

Bremen-Hemelingen,
Diedrich -Wilkens - Str. 39/45

Dipl.-Ing. Gottfried Hentschel, Bremen-Lesum,
has been named as the inventor

The invention relates to a power supply rectifier circuit for wireless communication technology devices, preferably radio or television sets, using a transformer, where the voltage is switched by selecting an appropriate tap point on the Primary winding takes place. It is well known that a transformer of this type is also called an autotransformer.

With simple receiving devices, preferably with
Radio receivers in the low price range will be io
mostly used autotransformers. They consist of the primary winding connected to the network and an iron core, but only have one
smaller secondary winding, which is only used to generate the heating voltage for the tubes. The 15th
also required, but higher anode voltage
is taken directly from the primary winding. Since the anode voltage should have as high a value as possible, the primary winding at the upper end of this type of transformer _{will be dimensioned 20 s0} so that it is substantially tapped. As a result, when operating from the savings in its construction compared to a nor-220-volt network, the connected rectifier array full network transformer will hardly be able to produce the anode DC voltage.

too fed directly from the grid. The transformer The invention is based on the object

in this case is only to be designed with the power for the 25 mains connection rectifier circuit, generation of the heating voltage loaded and could thus that the load on the mains transformer when proportional can be kept small. However, both the highest and the lowest are very close often also the operation of the device, for example the mains voltage provided, if possible wisely desired on 110-volt networks. As a result, it must be the same in each case and it is therefore at the smallest possible Transformer then the entire anode output 30 percent effort for all common mains voltages from 110 volts to approximately 220 volts can be used equally well, mize, i.e. it must be based on the existing mains voltage. There is a rectifier circuit for mains connection

from 110 volts to almost another 110 volts has become known, which also has an autotransforcing. It must also be taken into account that is used with the mator. But this circuit is for Connection of one mostly working in one-way circuit- 35 all-current use determined and designed so that the rectifier is the effective value of it - it without special switching both at the co-flowing Pulse currents over twice as high as the power grid as well as operated on the alternating current grid the anode direct current supplied by the rectifier. can be. As a result, their structure is also up If, for example, 60 mA anode direct current is used for this task and therefore shows required so the rms value of the dated trans- 40 which the operation of this circuit both with formator to be delivered to the rectifier pulse direct current as well as alternating current allow the

current about 140 mA. It also contains direct current and harmonic components that Adversely affect the magnetization of the iron core.

If one considers the operating conditions on the basis of the above-mentioned operating example a known autotransformer of the type described above, it would have to be connected to a

but cannot serve to ensure an even load on all winding parts of the transformer to bring about different mains voltages. This object is achieved by the invention Circuit solved by connecting the rectifier to the primary winding of the transformer, namely to a tap is connected which is in the middle between the connections for the minimal and

110-volt network with a premagnetized iron core of the 50 maximum permissible network voltage for the relevant

Transformer has an output of 110 volts · 140 mA transformer.

= 15.4 watts can be applied. As a result, you have to take it as the highest common mains voltage

in order to avoid damaging overloads, the wicks should be 220 volts and 110 volts as the lowest

of an autotransformer of this type, the tapping point was attached to the primary winding.

709 848/236

Claims (2)

for example 165 volts. Assuming that the rectifier arrangement, as already mentioned, has to be fed with a pulse current of about 140 mA, a load of 55 volts * 140 arises for the transformer when it is connected to a 220 volt network by stepping it down to 165 volts mA = 7.7 watts. If it is connected to a 110-volt network, a power of 55 volts · 140 mA = 7.7 watts must also be applied by stepping up to 165 volts. It is thus achieved that an autotransformer according to the invention is always evenly loaded both when operating on the 220-volts network and on the 110-volt network and can also be made much smaller and more space-saving thanks to weaker windings. Another advantage is that the number of turns through which the direct current flows is smaller, and with it the premagnetization of the iron core. A further saving in construction costs and thus an expansion of the mains connection rectifier circuit to a complete mains supply circuit is achieved in that another tap is arranged on the primary winding for tapping the heating voltage, preferably for tubular heating filaments connected in series, so that in itself known Way, the secondary winding is omitted and the transformer becomes even smaller as a result. In the drawing, exemplary embodiments of the subject matter of the invention are shown and compared with the previous type of autotransformer. 1 shows the diagram of an autotransformer of conventional design with mains connections for 220 and 110 volts on the primary winding P. A secondary winding ν? intended. The tap for the rectifier arrangement G for generating the required DC anode voltage is located directly at the upper end of the primary winding P. This means that the rectifier arrangement is directly connected to the mains when the transformer is connected to 220 volts. In this case, the transformer is only loaded with the power for the tube heating and the losses. If, on the other hand, it is operated from a 110-volt network, it must also provide the power for transforming the mains voltage from 110 volts to the 220 volts required for the anode current rectifier G and accordingly be dimensioned according to this maximum output. This does not result in any significant savings compared to the normal full-line transformer. In Fig. 2 the arrangement according to the invention is shown. Here the connection for the rectifier arrangement G has been placed between the feed points for the 220-volt and 110-volt mains connection to the primary winding P. This means that only an anode voltage of, for example, 165 volts is available, but only half as much power has to be applied by the transformer when it is operated on a 220-volt network or on a 110-volt network as when connected to the upper end of the primary winding P in the circuit of the known autotransformers according to FIG. 1. As a result, the winding only needs to be made half as strong. Fig. 3 shows a further simplification in the form that the tap for heating the tubes with, for example, 50 volts or more for series-connected filaments was placed directly on the primary winding P. Above all, this means that the secondary winding 5 "is omitted, so that the transformer can be kept even smaller. Patenta.vsphOchr 1. Mains connection rectifier circuit for wireless communications equipment, preferably radio or television sets, using a transformer in which the voltage is switched by selecting an appropriate tap on the primary winding, characterized in that the rectifier (G) is connected to the primary winding (P ) connected to a tap. which lies in the middle between the connections for the minimum and maximum permissible mains voltage for the transformer in question. 2. Extension of a mains connection rectifier circuit according to claim 1 to a mains supply circuit, characterized in that the only existing winding of an autotransformer Another tapping point is provided for taking the heating voltage for the heating filaments of the tubes, which are preferably connected in series is. Considered publications: German Patent Specifications No. 680 757, 680 758. 1 sheet of drawings © 709 848 236 12.57