Novel thermoelectric temperature sensors

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000230-000233 ◽  
Author(s):  
L. Rebenklau ◽  
K. Irrgang ◽  
A. Wodtke ◽  
K. Augsburg ◽  
F. Bechtold ◽  
...  

Nearly every industrial application needs temperature measurement. Typical temperature sensors are based on thermocouples or resistance elements. Nevertheless, these sensors are not always desired for every application. For example, temperature sensing of fluids or gases in pipes. A standard sensor inside such a material flow has an influence on the flow itself (flow resistance, turbulences) which would lead to incorrect temperature result. Additionally, application that need periodical cleaning of their pipe system (food or pharmaceutical production) can't use such sensors because of hygienically reasons. Novel thermoelectric temperature sensors, which could reduce the previously demonstrated problems have been developed as part of a research project. The basic idea of the novel sensor concept is to use thick film technology to enable novel sensor geometries. The typical use of thick film technology is realization of ceramic circuit boards, in which metal-based thick film pastes were screen printed and fired as conductive material. The sensor concept uses a combination of different commercially available metal-based pastes (platinum, silver, nickel, gold) to creates thermocouples based on the Seebeck effect.

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000053-000057
Author(s):  
Jaroslaw Kita ◽  
Sven Wiegärtner ◽  
Alistair Prince ◽  
Peter Weigand ◽  
Ralf Moos

Abstract The application of thermocouples as temperature sensors has been well known and has already been established for many years. However, for classical thick-film technology using screen-printing and firing, no standardized solutions exist. The here-presented newly developed PtRh thick-film compositions (90% Pt,10% Rh) allows to construct thick-film type S thermocouples (Pt/PtRh), following the IEC temperature characteristics. They can be fired in air, and therefore can be easily integrated into existing thick-film components and devices. In an earlier study, the new Pt-Rh composition was successfully tested on alumina substrates. Their electrical characteristics is equal with classical wire type S thermocouples. This study continues the investigations of thick-film thermocouples. We tested the newly developed pastes for high temperature applications on alumina substrates and evaluated the application of the new screen-printable type S thermocouples on LTCC ceramics. Three possible configurations were investigated: deposited on already fired LTCC substrates (post-fired), screen-printed and co-fired with LTCC tapes on the top surface as well as as buried structures. The paper presents the results of our evaluation and discusses further possible applications.


1977 ◽  
Vol 4 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Per Chr. Malmin

During the last few years, the use of hybrid integrated circuits in microwave radio links has increased significantly. This paper reports on a range of microwave hybrid circuits now in production at our plant. These include transistor high power amplifiers, low noise mixers and various other circuits. The hybrid technology has proven to be cost competitive with the more conventional waveguide and coaxial technologies, and gives quite a few other advantages as well. Among these, the standardization of packages and modules is discussed in some detail. The trend is now to use the hybrid technology in VHF circuits as well. This opens up the possibility of integrating related functions in one package. The production cost in this case must be related to printed circuit boards, and it remains to be seen if there is anything to gain in this respect. However the reduction of the size of modules and the time for circuit alignment will certainly give an improvement in the overall system cost. In order to reduce the cost of microwave hybrid circuits, thick film technology is currently being investigated for use up to 15 GHz. There is probably no specific upper frequency for thick film circuits, but the possibility of using conventional thick film technology depends on the actual circuits under consideration. Preliminary results of this work are reported, together with a cost comparison between thick film and thin film microwave hybrid circuits.


Author(s):  
Bhanu Sood ◽  
Diganta Das ◽  
Michael H. Azarian ◽  
Michael Pecht

Abstract Negative resistance drift in thick film chip resistors in high temperature and high humidity application conditions was investigated. This paper reports on the investigation of possible causes including formation of current leakage paths on the printed circuit board, delamination between the resistor protective coating and laser trim, and the possibility of silver migration or copper dendrite formation. Analysis was performed on a set of circuit boards exhibiting failures due to this phenomenon. Electrical tests after mechanical and chemical modifications showed that the drift was most likely caused by moisture ingress that created a conductive path across the laser trim.


1976 ◽  
Vol 22 (11-12) ◽  
pp. 791
Author(s):  
R. Naylor

1988 ◽  
Vol 135 (4) ◽  
pp. 77 ◽  
Author(s):  
J.E. Brignell ◽  
N.M. White ◽  
A.W.J. Cranny

1986 ◽  
Vol 3 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Q.M. Reynolds ◽  
M.G. Norton

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