SU87722A1 - A device for measuring the DC voltage of the total voltage of various frequencies - Google Patents

Description

The subject of the invention is a device for measuring a constant voltage in a mixture of voltages of different frequencies.

The known devices of the same designation, made according to the bridge scheme with active resistances included in one pair of opposite shoulders, and successively connected inductive and capacitance resistances in the other pair, do not ensure complete separation of the constant and variable components.

In the present invention, this disadvantage is eliminated by the use of electron tubes.

The device consists of two three-electrode lamps, switched in opposite, with one v.j lamps automatically displaced onto the grid, ensuring the difference of currents in the anode circuits when the measured voltage is directly applied to the grids of both lamps.

FIG. 1 shows a diagram of the proposed device; in fig. 2 - curves of anode currents of both lamps from grid displacements.

The main part of the device is two electron tubes, L and L, which are switched in opposite. The measured voltage is applied to

the grid circuit of one lamp directly, and the grid circuit of the other lamp through the active resistance R. In the anode circuit of the lamps, load resistances R and RZ are included, the difference in voltage drops

where they are measured with a voltmeter, which are attached to the output resistance terminals R The operating points of the lamps are determined by their grid displacements.

In the absence of voltage at the input of the device (or short-circuited input), the negative bias on the grids of the lamps is close to point a of the characteristic (Fig. 2). The anode currents in the lamps are small and the additional grid displacement on the lamp L taken from the resistance is small. The operating points of both lamps are close to each other. For this case, the difference between the anode currents and, consequently, the output voltage is small and the voltmeter reading is close to zero.

If a device is supplied with a voltage that has a constant and variable components, then the anode currents in the lamps will increase, but due to the appearance of an additional bias on the v7i lamp, the increase in the currents in the lamps will not be the same. The operating points of both lamps, moving upward along the characteristic (FIG. 2), will simultaneously move away from each other.

The difference in anode currents will increase in proportion to the constant component at the input of the device. Since the gain of the variable component is almost independent of the position of the operating point, if it is in the straight line segment and if no single value of the variable component (amplitude) goes beyond the straight line part of the characteristic, then within these limits the difference of the voltage on the load resistances, the constant component at the input will be proportional (Fig. 2). Thus, the voltmeter shows the value of a constant measured voltage (J.

This scheme allows the constant component of the voltage to be separated from the variable even at a very low frequency (Hz).

Subject invention

A device for measuring a constant voltage in a mixture of voltages of different frequencies of a lamp voltmeter type, characterized in that it is composed of two three-electrode lamps in opposite switching with automatic displacement of one of the lamps on the grid, which ensures the difference of currents in the anode circuits during direct supply measured voltage across the grids of both lamps.

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No. 87722

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