SU363179A1 - INFRANIZED FREQUENCY AMPLIFIER - Google Patents

Description

one

The invention relates to the field of radio engineering and can be used in electronic amplifiers used to amplify electrical signals in the range of infra-low frequencies.

Known amplifier infralow frequencies, but made a bridge circuit, two adjacent arms which contain transistors, and the other two - electrolytic tetrodes.

To obtain a small output level drift, careful selection of identical amplifying elements included in the shoulders of the amplifier bridge is necessary. This makes it difficult to use transistors, and especially electrolytic tetrodes, as amplifying elements.

The purpose of the invention is to reduce the output level drift.

The goal is achieved by the fact that the output of the tetrode of one of the arms of the amplifier is connected to the output of an additional balancing tetrode, the input of which is connected to a common point of the circuit.

The drawing shows the circuit amplifier.

The output currents / i and / 2 of the electrolytic tetrodes Y and 2 are simultaneously the input currents of the transistors 3 TL 4. The magnitudes of these currents at the same bias do not match.

Therefore, to obtain a zero level of the output signal with the same load resistors 5 and 6, in the process of tuning, the asymmetry is introduced into the output transistors with a potentiometer 7. This asymmetry leads to a drift of the exit level in the dynamical one.

In order to reduce this drift into the input circuit of the transistor 3, turn on the symmetrical electrolytic tetrode 8, the output current of which J3 J2-Jj is set by selecting) displacement array, removed from the divider on the resistors 9 and 10.

Subject invention

An infra-low frequency amplifier made according to a bridge circuit, the two adjacent arms of which contain transistors and the other two electrolytic tetrodes, characterized in that, in order to reduce the output level drift, to the output of the tetrode of one of the arms of the amplifier connects the output of an additional balancing tetrode whose input connected to a common point of the circuit.