SU67092A1 - Lamp detector - Google Patents

Description

In direct-fired radio receivers, considerable difficulty is the design of output detectors with offset (cut-off, minimum limit) necessary to obtain a delay in automatic volume control and to cut off noise in output devices of telegraph radio receivers with automatic recording.

Known cut-off detection circuits require isolated power supplies, high stability of power batteries and very precise impedance fittings or have very high internal resistances and can only be used with significant anode load resistances. The essence of the invention is that the alternating voltage to be rectified is supplied simultaneously to the anode circuit and to the triode grid circuit, and the cut-off voltage is only included in the triode grid circuit, which frees the proposed circuit from the disadvantages of the known circuits.

In FIG. 1-4 are known circuits having the above disadvantages, and FIG. 5-6 proposed detector circuitry.

The anodic circuits of the proposed circuits (Figs. 5 and 6) are free from power sources, so that the transition to the grids of the following lamps is simplified. From this point of view, the proposed schemes are equivalent to the scheme of FIG. 4. At the same time, the proposed schemes have a small internal resistance due to the use of both anode and grid circuits.

Compared with the widely used anodic detection circuit (Fig. 1), the proposed circuit also has the advantage of a significantly higher slope of the detection characteristic when operating with cut-off on ohmic load 1 with other similar properties.

Subject invention

A lamp detector with applied grid bias and a load in the anode circuit is distinguished by the fact that the detected voltage is applied simultaneously to the anode circuit and to the grid circuit.

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