SU621067A1 - Dc amplifier - Google Patents

Description

(54) DC POWER AMPLIFIER

one

The invention can be used in automation devices, computing and instrumentation technology.

A DC amplifier is known, which contains a series-connected input stage, a storage capacitor, an intermediate and output stages, and a switch connected parallel to the input of the intermediate stage l.

The purpose of the invention is to reduce the drift zero.

For this, a direct current amplifier containing a series-connected input stage, a light capacitor, an intermediate and an input stage, and a switch connected in parallel to the input of the intermediate stage, in parallel with the output of the output stage, is connected to the auxiliary input of the input stage.

The drawing shows the structural scheme of the proposed DC amplifier.

The DC amplifier contains input-connected in series 1, storage capacitor 2, intermediate 3 and output 4 stages, switch 5 connected in parallel with intermediate input Cascade 3, and resistive voltage divider b connected in parallel with output output of stage 4. Moreover 6 is connected to the auxiliary input of the input stage 1.

The DC amplifier operates in the following way.

Resistive voltage divider 6, introduced into the DC amplifier, forms a negative communication processing circuit from the output of the DC control to the auxiliary input of the input stage 1.

The transmission coefficient of the feedback circuit is set inversely proportional to the product of the coefficient: gains of all stages, i.e.

, о.с.

.)

 where K, and g. - feedback circuit transmission coefficient;

five

- the gain of the input stage on the auxiliary input;

To JCj, j, respectively, the gains of the intermediate and

Claims (1)

G): output stages. The direct current amplifier operates in two modes: the storage memory of the resting voltage and the operating mode. . In pei) f (HMe memorization of the output voltage, the rest key is closed. With trm on the storage capacitor 2, the voltage U is set, conditioned by the output voltage of the rest 1 UoBbix) of the intermediate 3 (,,) and output 4 (, ) cad cad, V, ",; (o.b.x / v ,, operating mode, when the key S is opened the memory coideris 2 is turned on, so that the voltage compensates the output voltage of the rest of the input 1, alternating 3 and output 4 stages. Indeed, in the absence of an input signal, the output voltage of the DC control. (Uoun) operating mode is done according to the following expression: o, b..y.a. o ,,, - and, UK -K-K .V-II V to output 1 and I zhwh- from where-about. 5.K ,, K Taking into account the expressions (1) and (2), they obtain that, in the ideal case, the output voltage of the DCF () in the operating mode is zero. The degree of compensation The output voltage of the DCF substantially depends on the fulfillment of relation (1), therefore, the proposed scheme is expedient to apply in those cases when the values of K i y depend little on the external operating conditions of the DCA. In the proposed DC amplifier, the magnitude of the temperature drift of the output voltage of the rest, brought to the input of the DCF, is the tenth of a µV / degree. DETAILED DESCRIPTION OF THE INVENTION A direct current amplifier comprising a series-connected input stage, a storage capacitor, an intermediate and output stages, and a switch connected in parallel with the input of the intermediate stage, which is provided with a switch. In order to reduce the zero drift, a resistive voltage divider is inserted parallel to the output of the output stage, the output of which is connected to the auxiliary input of the input stage. Sources of information taken into consideration during the examination: 1. D. Polonnikov. Decisive amplifiers, M., Energie, 1973, fig. 313. g h - "