Abstract
Transition Edge Sensors (TES) technology is among the most mature within the various Low Temperature Devices. These versatile devices can be used both as microcalorimeters or bolometers and tailored to different types of radiation by proper selection of the absorber layer materials and geometry. These sensors are designed and produced almost routinely in many laboratories with a good yield of devices reaching the design goals. The co-developing readout electronics for these TES systems, based on SQUID with various multiplexing schemes (time domain, frequency domain, code domain), is improving with each new instrument design and is foreseeable that instruments having many thousands of pixels are within reach in the next few years allowing the development of a new generation of spectroscopic/imaging instruments. In general the current performances of TES-based systems potentially allow to disclose new scenarios in the field of spectroscopy also for laboratory applications. This proceeding paper presents a brief overview of the TES detectors characteristics from the system engineering point of view and a panorama of some application in space and on ground.