SU1608539A1 - Apparatus for measuring thermo-emf of filamentary crystals - Google Patents

Abstract

This invention relates to solid state physics. The purpose of the invention is to simplify the measurement process. To do this, a device containing the first and second current sources, the outputs of which are connected respectively to the internal terminals of the first and second pairs of current leads at the ends of the crystal, and a measuring device that is connected between the internal terminals of the first and second pairs of current leads, additionally introduces a phase splitter, two diodes and a control divisible voltage divider. The device allows to partially automate the measurement process, since two interconnected currents are set at once, heating the ends of the crystal to certain temperatures, and the resistance of the average contacts is excluded when determining the thermoEMF. 1 il.

Description

AND; ki konkr visible | x vano in

The decree relates to the section of the physical body - measurement of parameters that are relevant to the measurement of thermoelectric power of filaments, and can be used with the measuring technique. The aim of the invention is to simplify the measurement process.

The device allows one to partially automate the measurement process, since two interconnected currents are set at once, heating the ends of the crystal to certain temperatures, and the determination of the thermopower D eliminates the resistance of the average contacts.

In the drawing, the Lredstavlenb functional cf (; ma of the proposed device.

Usage: for 1: 1; 1 thermopower of threadlike crystals contains 1 voltage source, controlled 2 voltage divider, phase splitter 3. current sources A and 5, measuring device 6. diodes 7 and 8 and two pairs of current terminals 9, 10 and 11, 12, which are connected to the sample under test 13 crystals.

The output of the voltage source 1 is connected to the input of the controlled voltage divider 2, the output of which is connected to the input of the phase splitter 3. The first and second outputs of the phase splitter 3 are connected respectively to the inputs of the first 4 and cheap 5 sources, the outputs of which are connected to the internal current terminals 10 and 11 the first and second pairs, respectively, between which measuring device 6 is connected. The external current collectors 9 and 12 of the first and second pairs of current leads are connected via the first 7 and second 8 diodes to a common bus, respectively. The controlled divider 2 includes resistances 14 and 15.

Sl

"GH-jjja

A phase splitter 3 is made, for example, on an operational amplifier 16, a transistor 17 and resistors 18 and 19, and current sources are based on a compensation circuit on an operational amplifier 20 and 21, transistors 22 and 23, and resistors 24 and 25.

The device works as follows.

The output voltage of source 1 is divided by controlled divider 2, split in phase by phase splitter 3 into two opposite signals that control sources of currents 4 and 5 (respectively, positive and negative currents).

The currents of sources 4 and 5 are closed, respectively, through the sections of the test sample 13 crystal and the diodes 7 and B on the common busbar, which they can unload. The measuring device records the potential difference between the internal current leads 10 and 11, respectively, of the first and second pairs of current leads.

The output currents of sources 4 and 5 are respectively equal

i4

Rib

Rl5

: rUi,

(one)

(2)

 R24R19 Rl4 + Rl5 I, - 1. Rl5,.

where Ui is the value of the output voltage of voltage source 1;

R is the resistance value of the i-resistor (corresponds to the position in the drawing).

The value of the crystal EMF is determined from the form 1

Ae-U6- (U RKIO-IS-RKII), (3)

where Us is the voltage value recorded by the measuring device 6;

Editor I.Gorn

Compiled by I.Atmanov Tech red by M. Morgenthal

RKIO and RKII are the resistance values of the current leads 10 and 11.

Since the directions of the currents U and Is through the current terminals 10 and 11 are opposite, and the absolute values of i and Is are chosen so that

ll4lRKio ll БЖкп,, (4) then the formula (3) takes the form

.,(five)

those. The measuring device 6 directly shows the value of the thermopower of the crystal. To determine the thermoelectric emf coefficient

and De / AT, it is necessary to know the temperature of the ends of the crystal, which are determined by the graduated dependences of the resistances of the ends of the crystal on temperature.

Claims (1)

The invention The device for measuring the thermopower of whisker crystals, containing the first and second current sources, the outputs of which are connected respectively to the internal terminals of the first and second pairs of current leads. and a measuring device which is connected between the internal terminals of the first and second 1-1 current output pairs, characterized in that, in order to simplify the measurement process, a phase-gap, two diodes, a controlled voltage divider and a voltage source, the output of which is connected, are added to it to the input of a controlled voltage divider, the output of which is connected to: the input of the phase splitter, the first and second outputs of which are connected respectively to the inputs of the first and second current sources, and the external outputs of the first and second pairs The leads are connected via the first and second diodes respectively to the common bus. Proofreader L. Beskid