SU1275478A1 - Variable conductivity unit - Google Patents

Abstract

The invention relates to the field of automation and computing. The purpose of the Invention is to simplify the design of the controllable conductivity unit. It contains current-setting resistors 1,2,3, amplifiers 4.5, summing amplifiers 6.7, differential amplifier 8, multiplier 9. In the absence of a control signal at one of the multiplier inputs, the conductivity of the block is zero. conductivity of the signal increases linearly and does not depend on the potential difference applied to the external terminals of the unit. 1 il.

Description

This invention relates to automation and computing.

The purpose of the invention is to simplify the design of the block,

The drawing shows a functional block diagram of controllable conductivity.

The block contains current-setting resistors 1–3, decoupling amplifiers A and 5, the second and first summing amplifiers 6 and 7, respectively, differential amplifier 8, multiplier 9, external leads 10 and 11, and control voltage source 12,

Pin 10 is connected via series-connected current resistors 1 - 3 to pin 11, and through decoupling amplifier 4 to the inverting input of differential amplifier B, the non-inverting input of which is connected to pin 11,

The output of the differential amplifier 8 is connected to the inverting input of the summing amplifier 6 and one input of the multiplier 9, to the other input of which the control voltage source 12 is connected. The output of the multiplier 9 is connected to the non-inverting input of summing amplifier 6 and the inverting input of summing amplifier 7, the non-inverting input of differential amplifier 8 is combined with the non-inverting inputs of summing amplifiers 6 and 7.

The unit of controlled conductivity operates as follows.

The conductivity between pins 10 and 11 depends on the magnitude of the control voltage Uy.

. Denote the value of conductivity between pins 10 and 11 as g, and the value of conductivity of each of the current-setting resistors 1 - 3 through

,

Let external potentials U and Ц, respectively, be applied to pins 10 and 11, and at the output of source 12, control potential Uy. When supplying potentials U, Uy and Uj, the circuit elements perform the following functions.

The decoupling amplifiers 4 and 5 provide isolation of the unit from the circuit to which it is connected. They have a high input impedance and a unit transfer coefficient, so that the output of the amplifier 4

the potential is equal to U, the potential at the output of the amplifier 5 is equal to U, and at the output of the differential amplifier 8, the potential of U –di is (U –U), since and, and.

The summing amplifier 6 has three inputs, two of which are non-inverting and one inverting, the summing amplifier 7 has two inputs, one of which is inverting.

and other non-inverts.

The signals applied to the inputs of summing amplifiers 6 and 7 are summed algebraically,

The multiplier 9 performs the multiplication operation.

, Ug K- U (-uU),

where Ug is the nofotential on the output of the permultiplier 9;

K - transfer coefficient of the multiplier 9,

On the investing input, the summing amplifier 6 supplies the potential —or :. .

uJ.-li "- (and, -i)

on one non-inverting input

Ug -k-i, (- whether) to u ,, (),

to another non-inverting input (+1 g

On its potential is equal Ug + Ug + and l and-K- and, li + i.

On the input, summing amplifier input 7 is applied to the potential.

 "-K- li uy,

on his change of tirkuyktion input)

. and

At its output, the potential is - (- KAU-Uy-). The current through the resistor 1 is equal to

It (i b g (Uy) g KUy-uU. G.

The current through the resistor 3 is equal to

,) g (KuU u,) g

 Ug dU g.

Claims (1)

Thus, I, i.e., the incoming current (from the voltage switch 10) is equal to the output current (at pin 11). The magnitude of the conductivity between the terminals 10 and 11 is determined by 1 g of K- and 1 Ti. The block has the properties of controlled conductivity, namely: the current is proportional to the potential difference between pins 10 and 11 and when the control signal is zero, and if there is a control signal, it is proportional to uU and Uy. Consequently, when g 0 (R-) a, with Viz {U [ay], g y increases linearly and does not depend on the potential difference applied to conclusions 10 and 11. EFFECT OF THE INVENTION The controllable conductivity unit containing the first and second summing amplifiers, the control source multiplier, differential amplifier connected by inputs through two decoupling amplifiers to external pins of the block, between which are connected three series-connected current supply resistors connected by common pins to the outputs of the first and W The first and second multiplier inputs are connected to the corresponding output of the control voltage source and to the output of a differential amplifier, the non-inverting input of which is connected to the non-inverting input of the first and the first non-inverting input of the second summing U9 amplifiers, characterized in that, in order to simplify the design of the unit in it the multiplier is connected respectively to the inverting input of the first and second non-inverting input of the second summing amplifiers, inverting in od second summing amplifier connected to the output of the differential amplifier.