DE1078642B - Arrangement for hum compensation on a half-wave rectifier - Google Patents

Description

The invention relates to an arrangement for hum compensation on a half-wave rectifier, the one without a transformer between a mains terminal and a smoothing arrangement consisting of a Series impedance and shunt capacitors, which leads to a consumer, in particular a television receiver. Especially in a television receiver occurs a relatively large power consumption, so that with conventional smoothing agents a adequate screening cannot be obtained. A substantial reinforcement of the smoothing agents however, it would be very expensive and take up a lot of space. In particular, can the number of turns of the choke cannot be increased arbitrarily, since then the voltage drop also increases, that of a rectifier arrangement that can be connected to the AC network without a transformer this type should be kept as low as possible.

Even with the use of smoothing capacitors, very large capacitance remains when using one single choke coil often has a ripple voltage of 1 to 2 V on the second smoothing capacitor.

With an arrangement of the type mentioned in the opening paragraph, these disadvantages are avoided and in extremely simple way, even with a considerable current drain, a very good elimination of the Hum component in the DC voltage if, according to the invention, parallel to the series connection of the rectifier and the series impedance of the smoothing arrangement, the series connection of an ohmic resistor and a capacitor is arranged and if the two members of the last-mentioned series circuit taking into account the other connected switching elements of the smoothing arrangement are dimensioned so that the ripple voltage occurring at the output terminals is at least largely is balanced.

For the sake of completeness, it should be noted that it is known in a regeneration circuit for dry batteries to put a resistor parallel to the half-wave rectifier. The task here is apply a significant amount of AC power to the battery being refreshed. It is also known in the case of a half-wave rectifier arrangement, the gas-filled rectifier tube has a capacitor in parallel to switch in order to avoid uneven changes in the current flowing through the rectifier. Obviously, these known arrangements are not concerned with the task of hum compensation and use the impedances connected in parallel to the rectifier for significantly different purposes.

It is also known to use an additional transformer or an additional transformer winding on the feed arrangement, which is already present, for hum compensation
on a half-wave rectifier

Applicant:

NV Philips' Gloeilampenfabrieken,
Eindhoven (Netherlands)

Representative: Dipl.-Ing. K. Lengner, patent attorney,
Hamburg 1, Mönckebergstr. 7th

Claimed priority:
Netherlands of March 27, 1956

Peter Johannes Hubertus Janssen,

Eindhoven (Netherlands),
has been named as the inventor

transformer to induce an alternating voltage in the circuit of the rectified voltage, which the At least partially removes ripple voltage. However, such facilities are costly and it is difficult to to give the correct phase to the additionally induced voltage.

The invention aims to improve the latter type in an extremely simple manner the remaining ripple voltage is properly balanced even if the current consumption of the Consumer is considerable.

The invention is explained in more detail using an exemplary embodiment shown in the drawing.

In the drawing, the input terminals of the device connected to the SOHz alternating current network are denoted by 1. The output terminals to which the direct current consumer is connected are labeled 2. Between the upper mains terminal and the upper connection terminal - which receives the positive polarity with respect to the lower one - there is a series connection of a rectifier 3 and a choke coil 4. The latter, together with the electrolytic capacitors 5 and 6, forms the smoothing part. These capacitors can have a capacity of 50 to 100 μΈ .

Despite this large capacity, the ripple voltage occurring at the output terminals is often always still too high. This can at least for the most part be compensated for if, according to the invention, in parallel for series connection of the rectifier 3 and the

90Ϊ 768/302

Choke coil 4, the series connection of a resistor 7 and a capacitor 8 is arranged.

The capacitors 8 and 6 together with the resistor 7 form a voltage divider between the mains terminals, which, with the correct choice of the capacitances of the capacitors and the resistance value, of the A compensation voltage of the correct size and phase is fed to the upper output terminal.

With a resistance 7 of 20,000 Ω, a capacitance of the capacitor 8 of 0.5 μ ¥ and a capacitance of the capacitor 6 of 50 μΡ, there was a reduction in the ripple voltage from IV to 0.14V in one case.

Claims (2)

Claims. _± - - -1. Arrangement for hum compensation a half-wave rectifier, which without a transformer between a mains terminal and a Smoothing arrangement, consisting of a series impedance and shunt capacitors, which is too a consumer, in particular a television receiver, leads, characterized in that parallel for series connection of the rectifier (3) and the series impedance (4) of the smoothing arrangement the series connection of an ohmic resistor (7) and a capacitor (8) is arranged is and that the two members of the last-mentioned series connection taking into account the rest connected switching elements of the smoothing arrangement are dimensioned so that the to the Output terminals occurring ripple voltage is at least largely balanced. 2. Arrangement according to claim 1, characterized in that reactive and effective resistance of the series connection (7, 8) of the same order of magnitude - are of the order. - - Considered publications: German patents "No. 390 605, 544 097, 372, 827 209, 904 194; U.S. Patent No. 1 93Q165; Wireless World, October 1955, pp. 503 and 504; Textbook of radio reception technology, 1948, by Pitsch, pp. 712 and 713. " 1 sheet of drawings © 909 768/302 J.