SU1020979A1 - Controlled resistant - Google Patents

Description

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This invention relates to a radio detector and can be used in various automatic control systems.

A known controlled resistance contains a field transmitter, to the drain of which are connected series-connected first and second resistors, the junction point of which is connected to the gate of the field-effect transistor, as well as a non-inverting op-amp amplifier with a negative OFAT circuit that converts the input of which is the control input Cl 3 signal

One well-known sadrotlenia has large non-linear distortions of the effect of effective cc ipo flow control.

The purpose of the invention - the reduction of neilina | w to distortion.

This goal is achieved by the fact that the control resistance contains a field-effect transistor, to the drain of which are connected in series the first and second resistors, the connection point of which is connected to the gate of the field-effect transistor, as well as non-inverted operational amplifier with a negative ofatrical connection and an inverter and an inverter. the input of which is the input of a go-round signal, a non-inverted operadonal amplifier is connected between the source of the fractional transistor and the second resistor.

In the drawing, the circuit is controlled electrically to a controlled resistance circuit. The controllable resistance is cokepsKHT field-effect transistor 1, first resistor 2, second resistor 3, non-inverted op-amp with 4 control circuits with negative feedback in additional additional 5 and 6 input 7

The controlled resistance operates as follows.

When the magnitude of the control signal at input 7 changes, the resistance of the field-effect transistor 1 changes. With the help of a non-inverted operational force. The element 4 eliminates the influence of the negative ofatomic coupling due to the influence of the parasitic source resistance of the fop transistor 1.

If the ssToro gain factor of the non-inverting operational gain

4with additional resistors

p R

5 and 6 choose equal to (+

P

n Attach to the gate polevokhche

About transistor 1 using the first resistor 2 and the second resistor 3 is half the drain-source voltage, then dependence. current flow through the field-effect transistor 1 on the magnitude of the voltage applied to it, is linear. ter, i.e.

 + 1p about 1p si I s about 2 si o

/ (Zio-ch,) si ...

where fc g drain current;

. p is the multiplier constant for the given instrument;

UQ - cut off voltage Z - shutter voltage - source; C voltage pToifrHCTpK. This means that the nonlinear distortions at the output of the controlled counterpoint | I are theoretically absent, and in practice there is essentially less nonlinear distortions of the actual device.

The controllable resistance has a low level of insertion of nonlinear distributions, which is achieved without complicating the design of the rational choice of the gain of a non-inverting operative amplifier.

Claims (1)

CONTROLLED RESISTANCE, containing a field-effect transistor, to the drain of which are connected series-connected first and second resistors, the connection point of which is connected to the gate of the field-effect transistor, and also a non-inverting operational amplifier with a negative processing circuit, the inverting input of which is an input of a controlled signal, about t and with the fact that, in order to reduce non-linear distortions, * a non-inverting operational G amplifier is connected between the source of the field-effect transistor and the second resistor rum.