Измерения с помощью датчиков, преобразователей, сенсоров
тензорезистор, датчик Холла
    Transducers, gauges, sensors -  Information portal  © 2011 - 2015                                                                                                            Use of material is possible by placing an active link
How to make a thermocouple

   It is not very difficult to make a thermocouple. There are some simple ways to make a thermocouple by your own hands using locally available materials and equipment. You can make a thermocouple on your own at home. See below the video how to make it.
You can make thermocouples for measurements and researches under laboratory (home) conditions on your own. For that purpose use the wires from materials, suitable to make a thermocouple, which are commercially available. The diameter of wire is important at measurements of thermal processes within small scope (researches of objects with small sizes). The less the diameter of thermocouple wire is, the less the error in determination of temperature and determination of parameters for thermal processes is, as the impact of thermocouple on heat exchange is reduced. The material of thermocouple is chosen depending on supposed range of working temperatures, required sensitivity, available secondary equipment, etc. The thermocouples of chromel-alumel, copper-constantan, etc. are most widely used.
   The process to make a thermocouple is to create a firm joint (welding, Fig. 3) of two materials (wires). To this effect, you may use a power source of sufficient capacity (for example, LACT - laboratory autoconnected transformer, car battery). Connect a thermocouple (both free ends) with wires 1, being previously mechanicall  y connected, to one pole of power source(Fig. 1), and a contact, being connected with a piece of graphite (for example, pencil 2) - to the second pole.
   The electrical arc arises and the wires of thermocouple are welded if you touch the graphite with connected ends of thermocouple. The voltage, necessary for welding, is selected on experimental basis starting from not large voltages of 3-5 V. The optimal value of voltage for welding depends on material of thermocouple, diameter, length and, as a rule, it does not exceed 40 - 50 V. At work it is necessary to observe safety precautions: Do not use too much voltage, do not touch the exposed parts of the electrical circuit. For the convenience of a small plot of thermocouple wires can be closed with tape, ceramic tube, and others.
   You can also receive rather good connection while heating the wires of thermocouple using an arc discharge that arises between them and a strong water solution of common salt.

устройства для сварки термопары
термопара до сварки
термопара после сварки
русский / english
Home >> Temperature, thermoelectricity. Thermocouple >> How to make a thermocouple. Video
Calibrating  of thermocouple (calibration charts)
For a condition, when a free end(shut) of thermocouple is at the zero of degrees celsius. A temperature is driven to °C, E.M.F. (tension) in mV.
chromel - alumel  (-270 °с   to  1370 °с)
platinum 30% rhodium platinum 60% rhodium
(0 °с   to  1820 °с)
chromel - constantan (-260 °с   to  1000 °с)
copper - constantan (-270 °с   to  400 °с)
chromel - kopel (-20 to 200 °с)

How to make a thermocouple of thermocouple
Преобразователь. Датчик температуры
General principles of transducers (sensors) 
    In the strict sense of the word transducer is a device that converts a change in one quantity changes in the other. In terms of electronic transmitter ... >>>
The principles of the transformation of the measured physical parameters 
    In each converter, which converts the element is based on certain physical principle, which is associated with the electrical characteristics of the device so that a change in the quantity being measured   >>>


Temperature, thermoelectricity

Magnetic fields

Mechanical stress, strain

Force, pressure, displacement, flow

Humidity, gases

Photo effects, light

Ionizing radiation

Electricity, capacity, piezoelectricity

Physical properties of materials

Literature on transducers

News, exhibitions, conferences

About the project. Contacts

датчики, сенсоры, измерительные преобразователи
Popular information
Temperature sensors, thermocouple             Sensors of mechanical stress
Force, pressure, flow                                    Phototransducers
Ionization transducers                                    Hall sensors
Датчик магнитного поля
   Sometimes thermocouple wires are soldered to make a thermocouple. The composition of solders for soldering of low temperature thermocouples: (melting temperature in °C - composition of solder is mentioned). 185 - 225 °С - Sn(37,5%) + Pb(60%) + Sb(2,5%);  183 - 230 °С - Sn(40 - 45 %) + Pb(60 - 55 %);  183 °С - Sn(63%) + Pb(37%);  180 - 225 °С - Sn(50%) + Pb(50%);  145 °С - Sn(50%) + Pb(32%) + Cd(18%);
Picture 2. Mechanical connection of two wires before welding.  Picture 3. How to make a thermocouple.
Electrical wiring diagram for welding thermocouple: