SU995017A1 - Device for measuring liquid capacity - Google Patents

Description

The invention relates to a measurement technique and can be applied in devices used for the investigation of liquid media.

A device for electrochemical studies of a liquid medium is known, which contains an electrolytic cell, a source of pulses and an amplifier. The disadvantage of the device is low accuracy due to the influence on the measurements of the floating potential and the adjacent electrode. . The closest to the invention to the technical essence is a device for measuring the capacitance of a fluid, containing an ed1 Electrolytic cell with closely spaced electrodes, the counter electrode of which is connected to the output of the operational amplifier, whose input is connected to the output of the pulse generator, differentiator, logic circuit for electric signal conversion C 2 .

The disadvantages of the known device are a large measurement time, the presence of a significant conversion error, due to the close arrangement of electrodes,

The goal of isoorestance is to increase the speed and accuracy of measurement. - the goal is achieved

In addition, a device containing an electrolytic cell with closely spaced electrodes, the counter electrode of which is connected to the output of an operational amplifier, whose input is connected to the output of a pulse, a differentiator, has a pulse distributor and transistors by the number of electrodes with a Schottky barrier, and the base The hiccup transistor is connected to one of the electrodes of the electrolytic cell; the emitters of all the transistors are connected to the inverting input of the operational amplifier, and the collectors to the outputs

20 pulse distributor.

The drawing shows a structural diagram of the device.

 The DEVICE contains an electrolytic cell 1 s closely located 25 H1 li1 electrodes 2, a counter electrode 3 connected to the output of an operational amplifier 4, transistors with a Schottky barrier 5, the collectors of which are connected to the outputs of the distributor 6 pulses, and the emitters

united in one point and connected to the inverting input of the operational amplifier 4, the differentiator 7, the input of which is connected to the counter electrode 3, the generator 8 of pulses, the output of which is connected to the input of the operational amplifier 4,

The device works as follows.

Having established a high potential at one of the outputs of the distributor 6 pulses, raise the potential at the collector of the corresponding transistor with a Schottky barrier 5, as a result of which it opens, an electric current will flow through a resistor connected to the emitters, if a pulse is supplied from the generator 8 pulses passing the current through the electrolytic cell,. The voltage drop resulting from this resistor is applied to the inverting input of opamp 4, and the voltage difference between the potentials the scrap at the output of the pulse generator 8 and at the inverting input of the amplifier 4 is amplified by the operational amplifier 4, the output of which is connected to the counter-electrode 3. As a result, the current through the electrolytic cell 1 is kept almost constant due to the high gain of the operational amplifier. The voltage on the counter-electrode 3 is fed to the input of the differentiator 7, the output voltage of which is proportional to the capacitance of the electrode, which is connected through the collector of the transistor with a Schottky barrier to the output of the pulse distributor 6, which is under high potential.

Since the remaining electrodes 2 are at a low constant potential, their effect on the measurement accuracy of the capacitance of the electrode under study is practically absent.

Schottky barrier transistors make it possible to quickly select the electrode under study in a non-contact manner, while eliminating the effect of one electrode on the other due to the absence of inverse gain, a low base-collector voltage.

The use of these transistors can significantly reduce the currents

flowing through the electrolytic cell, which improves measurement accuracy, reduces the dissolution of the electrodes and the formation of gaseous and solid substances on the electrodes. The error of the scatter of low and high potentials at the output of the pulse distributor 6 is also excluded, since the conductivity of the collector junction of the transistor with the Schottky barrier is very small. All this and the aggregate allows us to speed up the measurement process, to exclude a number of possible errors of measurement.

The device scheme allows simple docking with both electronic computer systems and devices for fixing measurement results.

The use of the proposed device makes it possible to determine the concentrations of substances at various points in the electrolytic cell, the dielectric constant, contact phenomena, electrochemical processes, and the dynamics of changes in the surface states of substances.

Claims (2)

Invention Formula A device for measuring fluid capacity, containing an electrolytic cell with closely spaced electrodes, the counter electrode of which is connected to the output of an operational amplifier, whose input is connected to the output of a pulse generator, a differentiator, characterized in that, in order to improve the speed and accuracy of measuring the capacity of a liquid, the device additionally contains a pulse distributor and transistors according to the number of electrodes with a Schottky barrier, and the base of each transistor is connected to one of the electrodes of the electrodes rolitic cell, the emitters of all transistors - with the inverting input of the operational amplifier, and collectors - with the outputs of the pulse distributor. Sources of information taken into account in the examination 11 USSR author's certificate No. 721730, cl. G 01 N 27/26, G978. 2. US patent 4173736, CL 324-5 published. 1966 (prototype).