DE1255724B - Circuit arrangement consisting of an ohmic resistor and capacitor connected in parallel, in particular for equalizers or simulated impedances - Google Patents

Description

Circuit arrangement consisting of an ohmic resistor connected in parallel and Capacitor, especially for equalizers or imitation impedances Die The invention relates to a circuit arrangement for forming a parallel circuit of ohmic resistance and capacitor with gradually changeable RC ratio.

In equalization circuits or simulated impedances, in particular of electrical communications and transmission technology, are often used with RC elements independently adjustable resistance and capacitance values are required. Such adjustability of the resistance and capacitance components is required if either the magnitude of the impedance or the phase angle or both should be changed. It is, provided that the phase angle should remain constant, the amount of the impedance for a particular desired frequency depends on the ratio of the ohmic resistance to the capacitance. The phase angle however, is at a desired frequency by the product of the ohmic resistance and capacity determined.

It is known to contribute to the purpose of changing the RC ratio to use such two-pole variable capacitors and potentiometers. Apart from that of the uncertainty factors occurring in such components you have a fairly large space to set it up, since variable capacitors and potentiometers cannot be kept arbitrarily small in their dimensions. This corresponding However, space is especially important when used in communication systems with small construction is provided, mostly not available. Another possible solution would be to replace or replace the two components depending on the RC ratio. Provide a series of resistance and capacitance levels and the change by switching over using solder bridges or plugs. Depending on the size of the range of variation, however, would be a more or less large number of individual capacitors and ohmic resistors necessary, so that here too the question of space would play a decisive role.

From the German Auslegeschrift 1151021, in particular F i g. 7, is it is already known to provide only one capacity with the help of a saving transformer Translated to a desired value via selectable taps of this transformer will.

From the F i g. 2 to 5 of German Patent 878 379 is about it In addition, the selectable translation of complex resistances by means of saving transformers is known.

The object of the invention is to create a changeable RC element, which is also well suited for use in very small constructions.

The circuit arrangement is designed according to the invention in such a way that that a fixed resistor and a fixed capacitance each to freely selectable taps a common economy transformer provided with taps are connected. This measure results in a considerable reduction in effort for a large number of possible adjustable RC combinations. A minimum of effort and space requirements can be achieved if the capacitor and ohmic resistor are dimensioned in this way are that fixed resistance and fixed capacitance at the same taps of the economy transformer can be switched on.

Using the known circuit arrangement according to FIG. 1 and the embodiment according to FIG. 2 the invention is explained in more detail.

In Fig. 1 shows a parallel circuit formed from a potentiometer and a variable capacitor, in which the RC ratio can be changed in a desired range. For example, if you want to change the capacitance by a factor of 5 for setting the impedance and the product RC between the limits 1 and 4 for phase setting, this results in a necessary setting range between 1/5 = 0.2 and 4l1 = 4 for the resistance, from which this results in an area that can be covered by a factor of 4 - 5 = 20. If one were to modify the known circuit arrangement in such a way that one turns the continuously variable RC element into a stepwise variable RC element, a large number of resistance values and capacitances would be required depending on the fineness of the gradation.

However, if, as shown in FIG. 2, one tapped several times Economy transformer, only a resistor and a fixed capacitance are required, to get the desired number of possible combinations.

In a savings transfer with z. B. ten winding connections a 2 ... a 6 and b 2 ... b 6 one obtains, for example, twenty-five useful capacitance values and thirty useful resistance values, whereby a total of 750 RC combinations can be carried out in a simple manner. Here it is possible to connect the capacitance to two fixed connections a2, b2 of the transformer and to connect the ohmic resistance to different taps and to choose different external terminals or to accept the ohmic resistance or its external terminals a1, b1 as fixed. It is also possible to make resistance, capacitance and external connections variable.

Claims (2)

Claims: 1. Circuit arrangement for forming a parallel connection of ohmic resistance and capacitor with gradually changeable RC ratio, characterized in that a fixed resistance and a fixed capacitance each separate to freely selectable taps of a common economy transformer provided with taps are turned on. 2. Circuit arrangement according to claim 1, characterized in that the capacitor and ohmic resistor are dimensioned so that the fixed resistance and fixed capacitance can be connected to the same taps of the economy transformer. Documents considered: German Patent No. 878 379; German interpretative document No. 1151.021 .